Step by Step Guide to Calling Web APIs in Power Query

Calling Web APIs in Power Query helps you get a lot of data from different online places. This skill is important for getting information from cloud services like Salesforce and Dynamics 365. But, you might face some problems while doing this. Users often have a hard time with API refreshes. Not all sources connect properly, but they might still work during refresh. Privacy level settings can also be tricky. It is important to keep things the same across data sources. Knowing about authentication, error handling, and data management is key to solving these issues.

Key Takeaways

• Learn why Web APIs are important. They help you get data from the internet easily.

• Pick the best way to log in, like OAuth 2.0 for safety or API Key for ease.

• Use the Power Query Web connector. It makes API calls easier and needs less coding.

• Use incremental refresh to only update data that changed. This saves time and helps performance.

• Follow good habits like setting query limits and using parameters. This makes your API calls more flexible and efficient.

Introduction to Web APIs

Web APIs act like bridges. They connect your apps to online data sources. This lets you access and change data stored in the cloud. It is important to know the data formats and rules used in these APIs. This helps you get data effectively.

Data Formats: JSON and XML

When using Web APIs, you will see two main data formats: JSON and XML. Here’s a quick comparison:

• JSON (JavaScript Object Notation):

  • It is shorter than XML, using simple name/value pairs.

  • Smaller files mean faster sending and processing.

  • It works well with JavaScript code, making it popular for web apps.

• XML (eXtensible Markup Language):

  • It can use extra information through attributes, which JSON does not have.

  • It is easier to read in browsers because of its tree structure, helping with debugging.

  • It can manage mixed content, allowing for more complex data setups.

JSON is made for sharing structured data, while XML is a way to mark up documents. This difference makes many developers prefer JSON today.

The Role of REST APIs

REST (Representational State Transfer) APIs are the most common type of APIs for accessing cloud data. They let you do things like getting, creating, updating, and deleting data online. REST APIs are popular because they are simple and lightweight compared to other types like SOAP, which needs strict XML formatting.

Setting Up Authentication for Web APIs

hen you connect to Web APIs, authentication is very important. It makes sure that only allowed users can see the data. You have different methods to pick from. Each method has its own good and bad points.

Different Authentication Methods

Here are some common ways to authenticate:

• Basic Authentication: This method uses a username and password. It is easy but not very safe.

• API Key Authentication: You send a special API key with each request. This key shows who you are and tracks your usage.

• OAuth 2.0: This method lets other apps access your data without sharing your login info. It is safer than basic authentication.

• JWT-based Authentication: JSON Web Tokens (JWT) are a small way to show claims. They help keep communication secure.

• OpenID Connect (OIDC): This builds on OAuth 2.0 for user login, adding more security.

Each method works best in certain situations. For example, OAuth 2.0 is popular for apps needing user permission. On the other hand, API Key Authentication is often used for server-to-server connections.

Tip: Always pick the authentication method that fits your security needs and app requirements.

Obtaining Authentication Tokens

To use OAuth 2.0 or similar methods, you need to get an authentication token. Here are the usual steps to follow:

1. Create an Identity Cloud Service client application: Set up your app with the right permissions.

2. Generate an access token: This token shows the permissions you want to give.

3. Provide the access token: Share it with developers who need access.

4. Configure access token validation: Make sure your service can check the token.

5. Issue requests against API endpoints: Include the access token in your requests for permission.

6. Refresh the access token: Make sure to refresh it when it runs out without needing admin help.

Following these steps helps you manage access safely.

Security Considerations

When setting up authentication, remember these security tips:

By following these tips, you can make your Web API connections safer.

Common Pitfalls

While setting up authentication, you might run into some common problems:

• Users often see invalid credentials errors, even with the right API key.

• Confusion can happen about where to put the API key in the request.

• Different authentication methods can cause issues, especially with anonymous and basic authentication.

Knowing about these problems can help you fix them better.

Making API Calls in Power Query

When you want to connect to Web APIs in Power Query, use the Web connector. This tool makes it easy to make API calls. It handles HTTP requests and responses for you. You don’t have to write hard code for each request. This automation makes your work easier.

Using the Web Connector

The Web connector helps you get web content from a URL. It wraps the data in the right document type, like Json.Document. Here are some important features of the Web connector:

• It allows advanced URL building and connection settings.

• You can add query parameters easily without escaping them.

• The Web API connector does not need a browser control, which is safer.

Here’s a table showing the configuration options in the Power Query Web connector:

Handling Paging in API Calls

When working with big datasets, you often need to manage paging in your API calls. Many Web APIs return data in pages to work better. Here are some tips for handling paging well:

1. Understand the Paging Mechanism: Different APIs use paging in different ways. Common methods include:

   • Offset and Limit Pagination: Uses parameters to set the starting point and number of records.

   • Cursor-Based Pagination: Uses a cursor based on a unique ID to get results.

   • Page-Based Pagination: Uses the page number and records per page for easy navigation.

2. Use a Web Connector: Build requests from a list of page numbers. This way, you avoid making many queries for each page.

3. Scheduled Refresh: Make sure your solution allows for scheduled automatic refresh in Power BI service. This feature keeps your data updated without needing to do it manually.

4. Include Pagination Metadata: Always add pagination metadata in API responses. This info helps you move through paginated data easily.

5. Know When to Stop Paging: Be aware of any paging parameters, like 'page size'. This helps you know when to stop asking for more pages.

By following these tips, you can manage API calls well and get large datasets without slowing down your application.

Custom Functions for Web API Calls

Custom functions are very important in the M language. They help when you work with Web APIs. These functions let you automate tasks that you do over and over, like making API calls. By writing code that you can use again, you can call these functions many times with different settings. This saves you time and effort. Here are some main benefits of using custom functions:

• They help automate tasks you do often.

• You can write code that you can use again for many calls.

• The M language has advanced features like error handling.

Using custom functions to automate API calls makes you more efficient. You can create functions that change based on your needs. This flexibility helps you get data from Web APIs better. Here are some benefits of using parameterized custom functions:

• They let you change parameters easily, which boosts efficiency.

• You make the query structure simpler, so it’s easier to manage.

• They help performance by letting you get data across many years or conditions without rewriting the query.

Custom functions can deal with complex data situations by taking many parameters. You can keep them in a separate query group to keep your workbook neat. When you use parameters, they help create fully dynamic ETL processes.

Common ways to use custom functions include wrapping API calls and using the List.Generate function for dynamic querying. This function lets you make many API calls based on the data you get back. Custom functions make it easier to make requests, so working with Web APIs is simpler.

Incremental Refresh with Web APIs

Incremental refresh is a useful idea. It lets you update only the data that has changed since your last refresh. Instead of reloading all the data, you only look at new or changed records. This method saves time and resources. It makes managing your data easier.

Importance of Incremental Refresh

Using incremental refresh has many important benefits:

• Reduced Resource Consumption: You refresh less data, which uses less memory and resources.

• Faster Refresh Times: By updating only the latest data, you make the refresh process much quicker.

• Efficient Management of Large Datasets: You can work with large data models without refreshing everything.

With incremental refresh, you can handle very large datasets, even billions of rows. This means you load data once and then just add the changes. As a result, report refresh times get better because you focus on the important data.

Performance and Resource Impact

Incremental refresh also improves performance and lowers resource use in Power Query. Here are some benefits:

• Faster Refresh: Only the changed data needs to be refreshed, saving time.

• More Reliable Refresh: You avoid keeping long connections to unstable source systems.

• Lower Resource Usage: Refreshing less data means using less memory overall.

By refreshing only the changed data, you make performance better and improve scalability. You can expect a big drop in processing time, resource use, and better system availability.

Technical Requirements for Incremental Refresh

To set up incremental refresh with Web APIs in Power Query, follow these steps:

1. Add parameters in the API call: key, q, and dt.

2. Create RangeStart and RangeEnd parameters that are Date/Time type.

3. Use a custom filter on the Date column based on RangeStart and RangeEnd.

4. Make sure the data types for parameters and columns match.

5. Set up the incremental refresh policy to manage data storage and refresh times.

By following these steps, you can set up incremental refresh well and enjoy its many benefits.

Error Handling in Web API Calls

When you use Web APIs, you might see different errors. Knowing these common problems helps you fix them better. Here are some usual errors you may run into:

• Data source errors: These happen when the API can't connect to the data source.

• Invalid object name error: This occurs in SQL databases when the needed data source is missing.

• Error handling necessity: Power Query must skip other steps if an error happens.

To fix authentication errors in your Web API calls, follow these steps:

1. Check your API Feed: Make sure the API is working well. It might work in Power BI Desktop but not in the web client.

2. Whitelist Power BI Domains: If proxy authentication is a problem, ask your network admin to whitelist the needed Power BI domains.

3. Collect a Trace in Power BI Desktop: Turn on tracing to help find the error by looking at the error log.

Using good error management practices is very important. Here are some best practices to think about:

• Error containment: Handle possible problems during API use to stop bigger failures.

• Utilize try expressions: These expressions help you manage errors smoothly without stopping everything.

• Centralize validation logic: Make sure bad data is marked and handled correctly.

To track Web API call failures, think about using logging and monitoring. You can use tools like Fiddler to check API responses easily. Also, access Power BI log files for help by turning on tracing in the options menu. User activity logs on the Power BI Service platform can give insights, but specific API call logs are key for fixing issues.

By knowing common errors and using best practices, you can improve your experience with Web APIs in Power Query.

---

In short, you can successfully call Web APIs in Power Query by doing these important steps:

1. Look at the API documentation to see what data you can get.

2. Find out what authentication is needed for the API.

3. Build the basic structure of your query based on the API's rules.

To make your work better, think about these best practices:

By paying attention to authentication, error handling, and good data management, you can make your API work easier and improve your overall workflow.

FAQ

What is a Web API?

A Web API helps apps talk to online services. It gives rules for getting and changing data on the internet.

How do I authenticate with a Web API?

You can log in using methods like API keys, OAuth, or Basic Authentication. Pick the method that works best for your security needs.

What is paging in API calls?

Paging helps handle big datasets by splitting them into smaller pieces. You ask for data one page at a time, which makes it faster and better.

How can I handle errors in Power Query?

Use try expressions to catch errors without stopping your work. Always check API responses for common problems like wrong credentials.

What is incremental refresh?

Incremental refresh updates only the data that has changed since the last time. This method saves time and resources, making it easier to manage data.