Pass Your Microsoft MCSD 70-487 Exam Easy!

Microsoft 70-487 (MCSD Developing Windows Azure and Web Services) exam dumps vce, practice test questions, study guide & video training course to study and pass quickly and easily. Microsoft 70-487 MCSD Developing Windows Azure and Web Services exam dumps & practice test questions and answers. You need avanset vce exam simulator in order to study the Microsoft MCSD 70-487 certification exam dumps & Microsoft MCSD 70-487 practice test questions in vce format.

Mastering Data Access for the 70-487 Exam

The Microsoft 70-487 exam, officially titled "Developing Microsoft Azure and Web Services," is a critical certification for developers aiming to validate their expertise in creating and managing robust services and applications in the cloud. This exam challenges a candidate's ability to design and implement services that access data, whether it's from a traditional relational database or a modern NoSQL store. A deep understanding of data access technologies is foundational to passing the 70-487 exam. This series will serve as a comprehensive guide, breaking down the core concepts and skills you need to master. In this first part, we will focus exclusively on accessing data.

We will explore the various data access technologies available within the .NET Framework, including the venerable ADO.NET and the powerful Object-Relational Mapper (ORM), Entity Framework. The discussion will delve into practical implementation details, such as querying and manipulating data using both frameworks, and highlight the scenarios where one might be preferred over the other. Furthermore, we will venture into the world of NoSQL by examining how to interact with Azure's storage solutions like Table Storage. Finally, we'll touch upon the importance of caching strategies to optimize data retrieval and enhance application performance, a key consideration for any high-performing web service.

Choosing the Right Data Access Technology

A fundamental skill tested in the 70-487 exam is the ability to select the appropriate data access technology for a given scenario. The choice primarily revolves around ADO.NET and Entity Framework. ADO.NET provides a low-level, high-performance way to interact directly with a data source. It gives the developer complete control over the SQL queries being executed, making it ideal for performance-critical operations or when working with complex legacy stored procedures. It operates in a connected or disconnected mode, using objects like SqlConnection, SqlCommand, and SqlDataReader for direct interaction and DataSet for offline data manipulation.

On the other hand, Entity Framework is a higher-level abstraction, an ORM that maps database tables to .NET objects. This allows developers to work with data using strongly-typed LINQ queries instead of raw SQL strings, which significantly reduces development time and minimizes the risk of SQL injection attacks. Entity Framework is better suited for applications where rapid development and maintainability are priorities over granular control of every database query. The 70-487 exam expects you to understand the trade-offs between the control and performance of ADO.NET and the productivity and abstraction of Entity Framework.

Querying Data with Entity Framework

Entity Framework simplifies data querying by allowing developers to use Language-Integrated Query (LINQ). This approach, known as LINQ to Entities, translates C# or VB.NET queries into SQL at runtime, abstracting away the underlying database language. When you write a query to retrieve data, you are working with your domain objects, not database tables. For example, to retrieve all customers from a specific city, you would write a simple LINQ query against a DbSet<Customer> collection within your DbContext. This makes the code more readable, maintainable, and less prone to errors than constructing SQL strings manually.

A crucial concept within Entity Framework is deferred execution. LINQ queries are not executed against the database at the point they are defined. Instead, execution is deferred until the results are actually enumerated, for instance, by calling methods like .ToList(), .ToArray(), or iterating over the query in a foreach loop. This feature enables developers to build up complex queries dynamically before sending a single, optimized query to the database. Understanding deferred execution is vital for writing efficient data access code and is a key topic for the 70-487 exam.

Manipulating Data Using Entity Framework

Beyond querying, Entity Framework provides a straightforward mechanism for creating, updating, and deleting records. These operations are managed through the DbContext, which acts as a unit of work. To add a new entity, you simply create an instance of your model class, populate its properties, and add it to the corresponding DbSet using the Add method. Similarly, to update an entity, you retrieve it from the database, modify its properties, and Entity Framework's change tracker automatically detects the modifications. Deleting an entity is as simple as retrieving it and passing it to the Remove method on the DbSet.

After performing any of these operations, you must call the SaveChanges method on your DbContext instance. This method is what actually executes the necessary INSERT, UPDATE, or DELETE commands against the database. The DbContext bundles all the changes made since it was instantiated (or since the last SaveChanges call) into a single transaction. This transactional behavior ensures data integrity, as all operations within the unit of work will either succeed together or fail together. Mastering this pattern of change tracking and saving is essential for building reliable applications and for success on the 70-487 exam.

Controlling Data Loading in Entity Framework

Entity Framework offers different strategies for loading related data, and choosing the right one can significantly impact performance. The default behavior is lazy loading. With lazy loading, related entities are not loaded from the database until they are explicitly accessed for the first time. For example, if you load a Customer object, its Orders collection will not be populated until you try to iterate over it. This is convenient but can lead to the "N+1" problem, where an initial query is followed by N subsequent queries to load related data, causing performance bottlenecks.

To combat this, developers can use eager loading. Eager loading allows you to specify which related entities should be loaded along with the main entity in a single database query. This is achieved using the Include method in your LINQ to Entities query. For instance, you can retrieve a customer and all of their orders in one database round trip. The 70-487 exam will test your understanding of when to use lazy loading for its convenience versus when to use eager loading to optimize database performance by reducing the number of queries.

Working with Data Using ADO.NET

While Entity Framework offers a high level of abstraction, ADO.NET remains a relevant and powerful technology for direct database interaction, a topic thoroughly covered in the 70-487 exam. ADO.NET provides a set of classes for connecting to a database, executing commands, and retrieving results. The core components include the SqlConnection for managing the connection, SqlCommand for defining the query or stored procedure to be executed, and SqlDataReader for reading a forward-only stream of rows from the data source. This connected model is highly efficient for reading large amounts of data with minimal memory overhead.

For scenarios requiring data to be manipulated offline, ADO.NET provides the disconnected model centered around the DataSet and SqlDataAdapter. A SqlDataAdapter acts as a bridge, filling a DataSet with data from the database and later reconciling changes from the DataSet back to the database. This approach is useful for applications that need to work with data without maintaining a persistent connection, such as a Windows Forms or WPF application. Understanding both the connected and disconnected models of ADO.NET is crucial for handling diverse data access requirements.

Executing Stored Procedures with ADO.NET

Many enterprise applications rely heavily on stored procedures for business logic, security, and performance. The 70-487 exam requires proficiency in executing these stored procedures using ADO.NET. To do this, you create a SqlCommand object and set its CommandType property to CommandType.StoredProcedure. You then provide the name of the stored procedure as the CommandText. Any parameters required by the stored procedure are added to the SqlCommand's Parameters collection. This approach is more secure than dynamic SQL as it prevents SQL injection attacks.

Parameters can be input, output, or both. For output parameters, you must specify the parameter's direction as ParameterDirection.Output before executing the command. After execution, you can retrieve the value of the output parameter from the same parameters collection. This mechanism is essential for stored procedures that need to return scalar values or status codes in addition to result sets. Being able to effectively call stored procedures and handle their various parameter types is a practical skill tested in real-world development and on the exam.

Introduction to Azure NoSQL Data

The modern application landscape, and consequently the 70-487 exam, extends beyond relational databases. Azure offers several NoSQL data storage options, including Azure Table Storage. Table Storage is a key-value store designed for storing large amounts of structured, non-relational data. It is highly scalable and cost-effective, making it suitable for applications that require storing terabytes of data like user profiles, logs, or device telemetry. Data is stored in tables, and each entity in a table has a composite key consisting of a PartitionKey and a RowKey, along with a timestamp.

The PartitionKey is crucial for scalability, as it determines how data is distributed across storage nodes. All entities with the same PartitionKey are stored together, allowing for efficient queries against a single partition. The RowKey uniquely identifies an entity within a given partition. Queries that specify both a PartitionKey and a RowKey are the most efficient. Understanding this keying strategy and how it impacts query performance and scalability is a core concept for anyone working with Azure Table Storage.

Performing Operations on Azure Table Storage

Interacting with Azure Table Storage programmatically is done via the Azure Storage Client Library for .NET. To perform operations, you first need to connect to your storage account using a connection string. You then get a reference to a CloudTableClient and, from that, a CloudTable object representing the table you want to work with. The library provides intuitive methods for performing CRUD (Create, Read, Update, Delete) operations. Entities you work with are typically represented by classes that inherit from TableEntity, which provides the required PartitionKey and RowKey properties.

To insert a new entity, you create an instance of your entity class, populate its properties, and create an Insert operation using TableOperation.Insert. Similarly, you can create retrieve, replace, or delete operations. These operations are then executed against the table. For efficiency, you can batch multiple operations that target the same partition key into a single atomic transaction using TableBatchOperation. This reduces the number of requests sent to the storage service and ensures that all operations in the batch succeed or fail as a single unit, a technique you should be familiar with for the 70-487 exam.

Implementing an Effective Caching Strategy

To build high-performance and scalable web services, a robust caching strategy is indispensable. Caching involves storing frequently accessed data in a temporary, fast-access storage location to reduce the latency and load on the primary data source, such as a database. The 70-487 exam expects developers to know how and when to implement caching. One common technique is in-memory caching, where data is stored in the web server's memory. This is the fastest form of caching but is limited by the server's RAM and is not shared across multiple server instances in a web farm.

For distributed applications, a distributed cache like Azure Cache for Redis is the preferred solution. It provides an external cache that can be shared by multiple application instances. This ensures data consistency across the web farm and allows the cache to scale independently of the application servers. The common pattern used is the "cache-aside" pattern. When an application needs data, it first checks the cache. If the data is found (a cache hit), it is returned directly. If not (a cache miss), the application retrieves the data from the database, stores it in the cache, and then returns it.

Designing and Implementing Resilient Web APIs for the 70-487 Exam

Building on the data access foundation established in the first part, this second installment of our 70-487 exam preparation series focuses on the core of modern service development: designing and implementing Web APIs. The 70-487 exam places a significant emphasis on a developer's ability to create scalable, secure, and maintainable HTTP-based services using ASP.NET Web API. These services are the backbone of today's distributed applications, providing the means for diverse clients—from mobile apps to single-page web applications—to communicate and interact with backend systems. A thorough grasp of Web API concepts is non-negotiable for achieving certification.

This part will guide you through the entire lifecycle of building a Web API. We will start with the fundamental principles of REST (Representational State Transfer) and how they translate into the design of your API's controllers and actions. We will then explore advanced topics such as implementing robust security measures, handling requests and responses effectively through content negotiation, and extending the API pipeline with custom filters and message handlers. Finally, we will cover the practical aspects of consuming these APIs from client applications and discuss the various options for hosting and deploying your services, including deploying to Microsoft Azure.

Understanding Core Web API and REST Principles

At the heart of ASP.NET Web API is the architectural style known as REST (Representational State Transfer). The 70-487 exam requires a solid understanding of its principles. REST is not a protocol but a set of constraints for building scalable web services. It leverages the standard HTTP protocol, using its verbs—GET, POST, PUT, DELETE, PATCH—to represent actions on resources. A resource is any piece of information that can be named, such as a customer or an order, and is identified by a URI (Uniform Resource Identifier). For example, a GET request to /api/customers/123 would be expected to retrieve the customer with an ID of 123.

Another key principle is that RESTful services should be stateless. This means that each request from a client to the server must contain all the information needed to understand and complete the request. The server does not store any client context between requests. This constraint enhances scalability, as any server instance can handle any client request. Finally, REST uses standard HTTP status codes to indicate the outcome of a request, such as 200 OK for success, 201 Created for successful resource creation, 404 Not Found when a resource doesn't exist, and 400 Bad Request for client errors.

Designing Web API Controllers and Actions

In ASP.NET Web API, the entry points for handling client requests are controllers. A controller is a class that inherits from ApiController and contains public methods known as actions. Each action corresponds to a specific HTTP request. The framework maps incoming requests to controllers and actions through a process called routing. The 70-487 exam covers two primary types of routing: convention-based routing and attribute routing. Convention-based routing defines global routing templates, typically in the WebApiConfig.cs file, that map URIs to controllers and actions based on a pattern.

Attribute routing, introduced in Web API 2, offers more control by allowing you to define routes directly on your controller actions using attributes like [Route]. For example, you can decorate an action with [HttpGet] and [Route("api/customers/{id}")] to explicitly map it to GET requests for a specific customer. Action methods can accept parameters that are bound from the request's URI or its body. The return type of an action is also flexible. While you can return your domain objects directly, it is best practice to return IHttpActionResult, which gives you full control over the HTTP response message, including the status code and content.

Implementing Dependency Injection in Web API

As applications grow in complexity, managing dependencies between components becomes challenging. The 70-487 exam expects developers to be proficient in applying software design patterns like Dependency Injection (DI) to create loosely coupled and maintainable code. DI is a pattern where an object's dependencies are "injected" from an external source rather than created internally. This makes the code easier to test, as you can substitute dependencies with mock implementations. In ASP.NET Web API, you can implement DI to manage the lifetime of components like repository classes or business logic services.

Web API provides a simple IDependencyResolver interface that you can implement to integrate with various Inversion of Control (IoC) containers, such as Unity, Autofac, or Ninject. The process involves creating an instance of your chosen container, registering your types and their corresponding interfaces, and then setting the global dependency resolver to your custom implementation. When Web API needs to create an instance of a controller, it will use your dependency resolver. The resolver will then create the controller and inject any required dependencies into its constructor, promoting a clean and modular application architecture.

Effective Request and Response Handling

A key feature of a well-designed Web API is its ability to handle various data formats. This is managed through a process called content negotiation. When a client sends a request, it can include an Accept header specifying the media types it can understand, such as application/json or application/xml. The Web API framework inspects this header and selects an appropriate media type formatter to serialize the response object into the requested format. Out of the box, Web API supports JSON and XML, but you can create custom formatters for other formats like CSV or protobuf.

The 70-487 exam will test your ability to configure and customize this behavior. You can modify the collection of formatters globally to add new ones or remove default ones. You can also influence the choice of formatter from within an action method. Understanding how to work with media type formatters is essential for building flexible APIs that can serve a wide range of clients. Properly handling request data, whether it comes from the URI, query string, or request body, and serializing response data into the client's desired format are core skills for any Web API developer.

Securing Your Web API

Security is a paramount concern for any web service, and the 70-487 exam dedicates a significant portion to this topic. Securing a Web API involves two distinct concepts: authentication and authorization. Authentication is the process of verifying a client's identity, proving they are who they say they are. Authorization is the process of determining whether an authenticated client has permission to access a specific resource or perform a certain action. A fundamental security practice is to enforce HTTPS (SSL/TLS) for all communication to encrypt data in transit and prevent eavesdropping.

For authentication, modern Web APIs often use token-based schemes, such as JSON Web Tokens (JWT). The client first authenticates with an identity provider using credentials, and in return, receives a signed token. This token is then included in the Authorization header of subsequent requests to the API. The API validates the token on each request to authenticate the client. For authorization, Web API provides the [Authorize] attribute. You can apply this attribute to entire controllers or individual actions to restrict access to authenticated users. You can also extend it for role-based ([Authorize(Roles = "Admin")]) or claims-based authorization for more granular control.

Extending the Pipeline with Filters and Handlers

ASP.NET Web API has an extensible request processing pipeline that allows you to inject custom logic for handling cross-cutting concerns like logging, error handling, or validation. The 70-487 exam requires knowledge of the different extension points, primarily filters and message handlers. Filters are attributes that can be applied to controllers or actions and execute at specific stages of the pipeline. There are several types of filters: Authorization filters run first to check permissions, Action filters run before and after an action method executes, and Exception filters run only if an unhandled exception occurs within an action.

Message handlers operate at a lower level than filters, working directly with the HttpRequestMessage and HttpResponseMessage objects. They are chained together and process the request before it reaches the routing dispatcher and process the response after it leaves the controller. Message handlers are suitable for tasks that need to inspect or modify the raw HTTP message, such as implementing a custom authentication scheme or adding a custom header to all responses. Understanding the difference between filters and message handlers and when to use each is key to building a clean and maintainable API.

Consuming Web API Services from .NET Clients

Once a Web API is built, it needs to be consumed by client applications. For .NET clients, the primary tool for this is the HttpClient class. HttpClient provides a modern, asynchronous API for sending HTTP requests and receiving HTTP responses from a resource identified by a URI. It is designed to be instantiated once and reused throughout the life of an application, as it manages underlying connection pooling efficiently. Creating a new HttpClient instance for each request can lead to socket exhaustion under heavy load, a common pitfall the 70-487 exam might test your awareness of.

When using HttpClient, all network operations should be performed asynchronously using the async and await keywords. Methods like GetAsync, PostAsync, PutAsync, and DeleteAsync return a Task<HttpResponseMessage>. You can then inspect the response's status code to determine if the request was successful and read the content using methods like ReadAsStringAsync or ReadAsAsync<T> to deserialize the response body directly into a .NET object. Properly handling asynchronous operations, managing the HttpClient lifecycle, and processing responses are essential skills for building responsive client applications.

Hosting and Deploying ASP.NET Web API

A Web API can be hosted in several ways, and the 70-487 exam expects you to be familiar with the options. The most common approach is to host it within an IIS (Internet Information Services) application, which provides a mature and robust environment with features for process management, logging, and security. Alternatively, a Web API can be self-hosted in any .NET process, such as a console application or a Windows Service. This is achieved using the OWIN (Open Web Interface for .NET) specification and the Katana project, which provides a flexible, decoupled hosting infrastructure.

For cloud-based solutions, the premier hosting option is Azure App Service. App Service is a fully managed platform (PaaS) that simplifies deployment and scaling. You can publish your Web API directly from Visual Studio or set up a continuous integration and continuous deployment (CI/CD) pipeline using Azure DevOps. Azure App Service offers features like custom domains, SSL certificates, auto-scaling, and deployment slots for staging environments. Understanding how to package your application and deploy it to these various hosting environments, especially Azure, is a critical competency for the modern developer.

Building and Deploying Robust Web Applications for the 70-487 Exam

Following our deep dive into data access and Web API design, the third part of our 70-487 exam series shifts focus to the development and deployment of web applications. While the exam title emphasizes Azure and web services, a significant portion of the objectives covers the core principles of building scalable and secure web applications using ASP.NET. These applications often act as the clients for the web services we have discussed or serve as the primary user-facing interface for a system. A candidate for the 70-487 certification must demonstrate proficiency in managing the application lifecycle, configuring security, and implementing performance optimizations.

In this installment, we will explore the fundamental architecture of ASP.NET applications, from understanding the request lifecycle to designing a multi-tiered structure. We will cover critical topics such as implementing authentication and authorization using ASP.NET Identity, managing application state effectively, and establishing robust error handling and logging mechanisms. Furthermore, we will delve into performance enhancement techniques like caching and real-time communication with SignalR. Finally, we will bring it all together by examining modern deployment strategies, with a particular focus on deploying to the Azure cloud platform.

Understanding the ASP.NET Application Lifecycle

To effectively build and troubleshoot ASP.NET applications, a developer must understand the application lifecycle, a key topic for the 70-487 exam. The lifecycle begins when the first request is made to the web server. The Application_Start event in the Global.asax.cs file is fired, which is the ideal place for one-time application initialization tasks, such as configuring routes or setting up dependency injection containers. For each subsequent HTTP request, a series of events are triggered within the ASP.NET pipeline. This pipeline processes the request, passing it through various HTTP modules before it reaches the appropriate HTTP handler, which is typically an ASP.NET page or an MVC controller.

Within the context of a single page request (for Web Forms), there is also a page lifecycle with its own set of events like Init, Load, PreRender, and Unload. While MVC and Web API have a more streamlined pipeline, the core concept of a request passing through distinct stages remains. Understanding these stages allows developers to inject custom logic at the right moment, whether it's for authentication, logging, or modifying the request or response. Familiarity with events like BeginRequest and EndRequest is crucial for implementing advanced application-wide behaviors.

Designing a Scalable Application Architecture

The 70-487 exam assesses your ability to design applications that are maintainable, testable, and scalable. A well-designed architecture is fundamental to achieving these goals. The most common architectural pattern is the N-tier (or multi-layered) architecture. This pattern separates the application into logical layers, with each layer having a specific responsibility. A typical three-tier setup includes a Presentation Layer (the user interface, e.g., an MVC project), a Business Logic Layer (BLL) containing the application's core logic and services, and a Data Access Layer (DAL) responsible for communicating with the database.

This separation of concerns makes the application easier to manage and modify. For example, you can change the underlying database technology by only updating the DAL, with no impact on the BLL or Presentation Layer. To further enhance this model, developers should apply SOLID design principles and use Dependency Injection to decouple the layers. Instead of the Presentation Layer directly instantiating BLL classes, it should depend on interfaces, with the concrete implementations being injected at runtime. This creates a flexible and highly testable system, which is a hallmark of professional software development.

Configuring Authentication with ASP.NET Identity

Securing a web application starts with robust authentication, and the modern standard for this in ASP.NET is ASP.NET Identity. The 70-487 exam requires proficiency in implementing this framework. ASP.NET Identity is a flexible system that allows you to manage users, passwords, profiles, roles, and claims. It is designed to work with various data stores, using Entity Framework by default to store user information in a SQL database, but it can be configured to use other providers. It provides a complete solution for user registration, login, password recovery, and profile management.

One of the key strengths of ASP.NET Identity is its support for external authentication providers using OAuth 2.0 and OpenID Connect. This allows users to log in with their existing accounts from social platforms like Google, Facebook, or Twitter, or with organizational accounts through Azure Active Directory. Integrating these external providers is a common requirement and involves registering your application with the provider to obtain credentials and then configuring the corresponding middleware in your application's startup code. This simplifies the user experience and offloads the burden of password management.

Implementing Authorization Logic

Once a user is authenticated, the next step is authorization: determining what they are allowed to do. ASP.NET provides several mechanisms for this. The simplest form is role-based authorization. Using ASP.NET Identity, you can create roles (e.g., "Admin", "Manager", "User") and assign users to them. Then, you can protect controllers or actions using the [Authorize(Roles = "Admin")] attribute, ensuring that only users in the specified role can access those resources. This approach is straightforward but can become rigid as the number of roles and permission rules grows.

For more granular control, ASP.NET supports claims-based authorization. A claim is a piece of information about a user, such as their name, email, or a specific permission like "CanEditProducts". During authentication, a user is issued an identity containing a set of claims. You can then create authorization policies that check for the presence of specific claims. For example, a policy could require a user to have a "Delete" claim on the "Products" resource. This approach is more flexible and expressive than role-based authorization and is a key concept for building secure, enterprise-level applications as tested by the 70-487 exam.

Managing Application State Effectively

Web applications built on the stateless HTTP protocol often need to maintain state between requests for a given user. ASP.NET provides several techniques for state management, and the 70-487 exam will test your ability to choose the appropriate one. For storing small amounts of user-specific data, Session state is a common choice. Session data is stored on the server and is associated with a user via a unique session ID, typically managed with a cookie. It is easy to use but can impact server memory and scalability, especially in a web farm unless a distributed session state provider is used.

Other options include client-side state management using cookies or hidden fields, which offload the storage burden to the client but are less secure and limited in size. For data that needs to be shared across all users and sessions, Application state can be used, though it requires careful handling of concurrency. Cache is another server-side mechanism that is not primarily for state management but can be used to store temporary data to improve performance. Understanding the scope, lifetime, and performance implications of each state management technique is crucial.

Implementing Robust Error Handling and Logging

A production-ready web application must handle errors gracefully and provide detailed logs for diagnostics. The 70-487 exam requires knowledge of best practices in this area. Unhandled exceptions can crash an application or expose sensitive information to the user. To prevent this, you should implement global error handling. In ASP.NET MVC, this can be done by creating a custom error filter that inherits from HandleErrorAttribute or by handling the Application_Error event in Global.asax.cs. This allows you to log the exception details and redirect the user to a friendly error page.

Logging is essential for monitoring application health and troubleshooting issues. Rather than writing custom logging code, it is best practice to use a mature logging framework like NLog, Serilog, or log4net. These frameworks provide a flexible and configurable way to record log messages. You can define different logging levels (e.g., Debug, Info, Warn, Error) and direct the output to various "sinks" or "targets," such as a text file, a database, or a cloud-based monitoring service like Azure Application Insights. Integrating a structured logging framework is a key skill for building maintainable applications.

Boosting Performance with Output Caching

Application performance is a critical concern, and caching is one of the most effective ways to improve it. The 70-487 exam covers various caching strategies, including output caching. Output caching allows you to store the rendered output of a page or controller action in memory. When a subsequent request is made for the same resource, the cached output is served directly without re-executing the code. This can dramatically reduce server load and improve response times for frequently accessed content that does not change often.

In ASP.NET MVC, you can apply output caching declaratively by adding the [OutputCache] attribute to an action method or an entire controller. You can configure the duration for which the content should be cached and specify parameters that should vary the cache, such as query string values or form post parameters (VaryByParam). For example, on a product details page, you could vary the cache by the product ID. This ensures that a unique cached version is stored for each product. Mastering output caching is essential for building fast and scalable web frontends.

Enabling Real-Time Communication with SignalR

Modern web applications often require real-time functionality, such as live chat, notifications, or dashboards that update automatically. Traditionally, this was achieved through inefficient techniques like polling. ASP.NET SignalR is a library that simplifies the process of adding real-time web functionality to applications, a topic relevant to the 70-487 exam. SignalR handles the complexity of connection management and allows for server-side code to push content to connected clients instantly as it becomes available.

SignalR uses a transport negotiation process, automatically selecting the best available communication method based on the capabilities of the server and client. It will use WebSockets if available, falling back to other techniques like Server-Sent Events or Long Polling if not. The developer interacts with a simple high-level API built around "Hubs." A Hub is a class on the server that client-side code can call methods on directly. Similarly, the server-side Hub code can call methods on the connected clients, enabling bidirectional communication.

Modern Web Application Deployment Strategies

Deploying a web application correctly is the final and crucial step in the development lifecycle. The 70-487 exam expects familiarity with modern deployment practices. While manual deployment by right-clicking "Publish" from Visual Studio is possible, automated deployment is the industry standard. This is achieved through Continuous Integration (CI) and Continuous Deployment (CD) pipelines, often managed with tools like Azure DevOps or Jenkins. A CI/CD pipeline automates the process of building, testing, and deploying the application whenever new code is committed to source control.

When deploying to Azure App Service, a powerful feature is deployment slots. A deployment slot is a live staging environment with its own hostname. You can deploy a new version of your application to a staging slot, test it thoroughly, and then "swap" it with the production slot. The swap operation is near-instantaneous and warms up the application in the staging slot before directing production traffic to it, resulting in zero-downtime deployments. This is a best practice for releasing updates without impacting users and is a key Azure feature to know for the exam.

Mastering WCF Services for the 70-487 Exam

As we progress in our comprehensive review for the 70-487 exam, this fourth part is dedicated to a technology that remains a cornerstone of many enterprise systems: Windows Communication Foundation (WCF). While newer technologies like ASP.NET Web API are often the focus for public-facing HTTP services, WCF provides a powerful and highly configurable framework for building services that require advanced features like varied transport protocols, robust security models, and distributed transactions. The 70-487 exam requires a solid understanding of WCF's architecture and capabilities, as it is still widely used in corporate environments for inter-service communication.

This installment will demystify WCF by breaking down its core components, famously known as the ABCs: Address, Binding, and Contract. We will walk through the process of creating and configuring WCF services, exploring the different hosting options available, from IIS to self-hosting in a Windows Service. A significant focus will be placed on the critical aspects of securing WCF services and managing transactions across service boundaries. We will also delve into instance and concurrency management, which are crucial for building scalable and reliable services. By the end of this part, you will have a clear understanding of where WCF fits in the modern development landscape.

The Core Concepts of WCF: ABC

To understand WCF, you must first grasp its fundamental building blocks, summarized by the acronym ABC. This is a foundational topic for the 70-487 exam. The 'A' stands for Address, which is the URI that specifies the location of the service. It tells a client where to send messages. The 'B' stands for Binding, which defines how the service communicates. The binding specifies the transport protocol to use (like HTTP, TCP, or MSMQ), the encoding for the messages (such as text or binary), and the security requirements. WCF provides a rich set of pre-built bindings to cover common scenarios.

The 'C' stands for Contract, which describes what the service does. The contract is an agreement between the service and the client, defined using a set of attributes. The [ServiceContract] attribute defines the interface for the service, while the [OperationContract] attribute is applied to the methods within that interface that will be exposed as service operations. Additionally, the [DataContract] and [DataMember] attributes are used to define the custom data types that will be passed between the client and the service. Together, the Address, Binding, and Contract define a service endpoint.

Creating and Configuring WCF Services

Creating a WCF service begins with defining the contracts. First, you create a C# interface and decorate it with the [ServiceContract] attribute. The methods in this interface that you want to expose are marked with [OperationContract]. Next, you create a class that implements this interface; this class contains the actual business logic for your service operations. The data types used as parameters or return values for these operations should be decorated with [DataContract] and their properties with [DataMember] if they are custom classes. This explicit opt-in model gives you precise control over what data is serialized.

Configuration is a critical aspect of WCF and a key area for the 70-487 exam. WCF services can be configured either declaratively in an app.config or web.config file or programmatically in code. The configuration file is where you define the service endpoints, specifying the address, binding, and contract for each one. This allows you to change how a service communicates—for example, switching from an insecure HTTP binding to a secure TCP binding—without recompiling the service code. Understanding the structure of the <system.serviceModel> configuration section is essential for managing WCF services.

Understanding WCF Bindings

The binding is arguably the most powerful component of a WCF endpoint, and the 70-487 exam will test your knowledge of the various options. Bindings control the transport, encoding, and protocol details of communication. WCF comes with a range of system-provided bindings for common scenarios. BasicHttpBinding, for example, is designed for maximum interoperability with older web services and clients, as it conforms to the WS-I Basic Profile 1.1. WSHttpBinding is also based on HTTP but supports more advanced features like reliable messaging, transactions, and robust message-level security, conforming to various WS-* standards.

For intranet scenarios where both the client and server are .NET applications, bindings like NetTcpBinding and NetNamedPipeBinding offer superior performance. NetTcpBinding uses TCP for communication across machines and provides a fast, secure, and reliable channel. NetNamedPipeBinding uses named pipes for inter-process communication on the same machine, which is the most performant option for that scenario. There is also NetMsmqBinding, which enables durable, disconnected communication using Microsoft Message Queuing (MSMQ). Choosing the correct binding is a critical design decision based on the application's requirements for performance, security, and interoperability.

Hosting WCF Services

Once a WCF service is built, it must be hosted in a running process so that clients can access it. The 70-487 exam covers several hosting options. One of the most common is hosting within Internet Information Services (IIS). When hosted in IIS, the service is activated by the first client request, and IIS manages the lifetime of the host process. This provides features like process recycling, idle shutdown, and health monitoring. This is a convenient option for services that use an HTTP-based binding.

Alternatively, a WCF service can be self-hosted in any managed .NET application, such as a console application or a Windows Service. This is done by using the ServiceHost class. You instantiate ServiceHost with the type of your service class, and it handles the creation of the communication stack and endpoints. Self-hosting provides maximum flexibility and control, as you are not dependent on IIS. It is the required option if you need to use non-HTTP transport protocols like TCP, named pipes, or MSMQ. Hosting in a Windows Service is ideal for long-running backend services that need to start automatically with the server.

Implementing Security in WCF Services

WCF offers a comprehensive and flexible security model, which is a critical topic for the 70-487 exam. Security can be broadly categorized into transport security and message security. Transport security secures the communication channel itself. For example, when using an HTTP binding, this would be achieved with SSL/TLS (HTTPS). With a TCP binding, it would also use TLS. Transport security is point-to-point, encrypting all traffic between the client and the server. It is generally easier to configure and more performant than message security.

Message security, on the other hand, secures the SOAP message itself by encrypting and digitally signing it. This provides end-to-end security, meaning the message remains secure even if it passes through multiple intermediaries before reaching its final destination. Message security is more flexible but has a higher performance overhead. WCF also provides a rich model for authentication, allowing you to validate clients using Windows credentials, username/password combinations, or X.509 certificates. You can configure these security settings through the binding configuration in your app.config or web.config file.

Managing Distributed Transactions

For enterprise applications that need to perform operations across multiple services or databases while maintaining data integrity, distributed transactions are essential. The 70-487 exam expects you to know how to implement them with WCF. WCF integrates with the Microsoft Distributed Transaction Coordinator (MSDTC) to enable transactional behavior. To make a service operation participate in a transaction, you decorate it with the [OperationBehavior(TransactionScopeRequired = true)] attribute. This ensures that the operation must be called from within a transaction.

On the client side, you wrap the call to the service operation within a TransactionScope block. When the client calls the service, the transaction context is automatically propagated from the client to the service. Any database operations or calls to other transactional services within that service method will enlist in the same distributed transaction. The binding must also be configured to support transaction flow, which is enabled on bindings like WSHttpBinding, NetTcpBinding, and NetMsmqBinding. If any part of the distributed operation fails, the entire transaction is rolled back across all participants.

Controlling Service Instancing and Concurrency

Understanding how WCF manages service instances and handles concurrent requests is vital for building scalable services. The [ServiceBehavior] attribute allows you to control this through the InstanceContextMode and ConcurrencyMode properties, a key configuration aspect covered in the 70-487 exam. InstanceContextMode determines how service instances are created. The default is PerCall, where a new service object is created for each client request. This is a highly scalable and stateless model. PerSession creates a new instance for each client session, maintaining state for that client across multiple calls. Single uses a single service object to handle all requests from all clients, which can be a bottleneck if not managed carefully.

ConcurrencyMode controls how threads access a service instance. The default is Single, which means only one request can be processed by an instance at a time. WCF synchronizes access, so you do not need to worry about thread safety, but this can limit throughput. Reentrant also allows only one thread at a time, but it releases the lock if the service makes an outbound call, allowing re-entrant callbacks. Multiple allows multiple requests to be processed by an instance simultaneously. This offers the highest throughput but requires the developer to make the service implementation thread-safe.

Final Preparation

As you prepare to take the 70-487 exam, consolidate your learning by focusing on the practical application of the concepts we've covered. The exam is not just about memorizing facts; it is about your ability to solve problems and make design decisions. Set up a free Azure account and get hands-on experience. Build a small Web API that connects to an Azure SQL Database and uses Azure Storage. Deploy it to an App Service and monitor it with Application Insights. Create a WCF service and host it in a console application.

Review the official exam objectives from Microsoft one last time and identify any areas where you feel less confident. Use practice exams to simulate the test environment and get a feel for the types of questions you will encounter. Pay close attention to case studies, which present a business problem and require you to design a solution using the technologies covered in the exam. On exam day, manage your time carefully, read each question thoroughly, and trust in the knowledge you have built. Good luck!

Go to testing centre with ease on our mind when you use Microsoft MCSD 70-487 vce exam dumps, practice test questions and answers. Microsoft 70-487 MCSD Developing Windows Azure and Web Services certification practice test questions and answers, study guide, exam dumps and video training course in vce format to help you study with ease. Prepare with confidence and study using Microsoft MCSD 70-487 exam dumps & practice test questions and answers vce from ExamCollection.