Azure Data Factory pagination using QueryParameters and body field

Question

Azure Data Factory pagination using QueryParameters and body field

Max Teitelbaum 0

Hello everyone,

I am currently working with a pagination system and facing a challenge with the URL and parameter concatenation. I am trying to append a specific string to the URL retrieved from the first page of an API response.

Here's the setup:

API Response Field: The initial URL https://api-prod.livegroup.co.uk/event/list?page_number=1&page_size=10 is returned in a field named nextPage.
Required Concatenation: I need to append the string &fields=title,start_date,last_modified to the URL mentioned above.
System Setup: I am using a pagination rules configuration where nextPage holds the base URL (from the body of the response), and I am attempting to append the fields parameter which includes the additional string.
Problem: I need to ensure that the nextPage URL is correctly concatenated with the &fields=... string for subsequent API requests in a way that the system correctly recognizes and processes it.

Here is how my current pagination rules configuration looks like:

Query Parameter: Set to modify fields with the value nextPage + &fields=title,start_date,last_modified

Despite these settings, I am not achieving the correct URL format needed for the API requests. I suspect the issue might be with how the concatenation is set up or perhaps there's a better way to configure these rules.

Could anyone suggest how to correctly configure these settings or point out what I might be doing wrong? Any help or pointers would be greatly appreciated!

ADF:
User's image NextPage field:

phemanth 15,755 Reputation points Microsoft External Staff Moderator

2024-05-10T08:14:26.5066667+00:00

@Max Teitelbaum

Thanks for using MS Q&A platform and posting your query.

The issue with your current pagination rules configuration is that you are using the plus sign (+) for concatenation, which is incorrect for URLs.

To fix this, you should use URL concatenation. URL concatenation uses an ampersand (&) to join multiple parameters together in a query string. For example:

https://api-prod.livegroup.co.uk/event/list?page_number=1&page_size=10&fields=title,start_date,last_modified

In your current configuration, you are setting the value of the fields parameter to be nextPage + "&fields=title,start_date,last_modified". This would result in a query string that looks like:

https://api-prod.livegroup.co.uk/event/list?page_number=1&page_size=10&fields=https://api-prod.livegroup.co.uk/event/list?page_number=2&page_size=10&fields=title,start_date,last_modified

This Might not work because the fields parameter is now set to the entire value of the nextPage parameter, rather than the string you want to append.

To fix this, you should modify your query parameter to use URL concatenation instead of the plus sign. Here is the corrected code:

Query Parameter: Set to modify fields with the value nextPage & "&fields=title,start_date,last_modified"

This will correctly concatenate the &fields=title,start_date,last_modified string to the nextPage URL

Hope this helps. Do let us know if you any further queries.
phemanth 15,755 Reputation points Microsoft External Staff Moderator

2024-05-13T05:57:35.61+00:00

@Max Teitelbaum We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
Max Teitelbaum 0 Reputation points

2024-05-28T05:28:17.8866667+00:00

Hello,

Thank you for your suggestion regarding the issue with the pagination rules configuration. I understand that using an ampersand (&) for URL concatenation is the correct approach here.

However, I'm a bit unsure about the absence of query parameters because it seems that the 'fields' will still need to be concatenated as a string. Also, if we're relying on the nextPage field from the body, it suggests that the base URL is already provided, allowing us to append additional parameters directly.

So, to clarify, are you suggesting we use the absolute URL method and directly append our string with nextPage & "&fields=title,start_date,last_modified"? This approach does seem straightforward as long as nextPage includes the necessary base URL.

Thanks again, and I look forward to your clarification to ensure I'm on the right track.

Best regards,

Max
phemanth 15,755 Reputation points Microsoft External Staff Moderator

2024-05-28T09:31:48.11+00:00
@Max Teitelbaum

Your understanding of the situation is spot on. Here's a breakdown of your points:

Concatenating fields: You're correct that the "fields" parameter still needs to be included as a comma-separated string, even when using the absolute URL method.

nextPage and base URL: Yes, the assumption is that the "nextPage" field within the response body already provides the complete URL, including the base URL and any existing query parameters. By appending "&fields=title,start_date,last_modified" to "nextPage", you're essentially adding the "fields" parameter to the existing URL.

So, if your "nextPage" response looks something like this: "nextPage": "https://api.example.com/data?limit=10&offset=20" Then, appending the fields parameter would be: "https://api.example.com/data?limit=10&offset=20&fields=title,start_date,last_modified"

This approach simplifies the code and avoids the need for manual base URL construction, as long as the "nextPage" field reliably provides the complete URL.

In summary, using the absolute URL method with "&fields=title,start_date,last_modified" appended to "nextPage" is the correct approach, assuming the provided URL includes the base URL and any existing query parameters.
Max Teitelbaum 0 Reputation points

2024-05-31T18:07:37.13+00:00

I've attempted to implement your suggested approach using several combinations, but unfortunately, I encountered some errors. Below are the details of the issues I faced:

The first error message indicated a failure on the 'Source' side with a specific error code relating to a failure in reading from a REST resource. The error message suggested an unexpected character issue in the parsing path. : "Failure happened on 'Source' side. ErrorCode=RestResourceReadFailed,'Type=Microsoft.DataTransfer.Common.Shared.HybridDeliveryException,Message=Fail to read from REST resource.,Source=Microsoft.DataTransfer.ClientLibrary,''Type=Newtonsoft.Json.JsonException,Message=Unexpected character while parsing path: ,Source=Newtonsoft.Json,'"

After modifying the nextPage parameter by removing the dollar sign, I encountered a different error. This time, the system reported an invalid pagination rule, again failing on the 'Source' side:

It errors out: Failure happened on 'Source' side. ErrorCode=RestInvalidPaginationRule,'Type=Microsoft.DataTransfer.Common.Shared.HybridDeliveryException,Message=Invalid PaginationRule, RuleKey='AbsoluteUrl', RuleValue='nextPage & "&fields=attendee_id,first_name,last_name,company,attendance_Status,delegate_Type,email,last_modified,registration_date"',Source=Microsoft.DataTransfer.ClientLibrary,'

Could you or anyone else suggest any alternative configurations that might resolve these issues? I'm eager to find a solution and would greatly appreciate any further assistance you can provide.
phemanth 15,755 Reputation points Microsoft External Staff Moderator

2024-06-03T05:58:55.0533333+00:00
@Max Teitelbaum

The errors you're encountering suggest there might be a couple of issues at play with your configuration. Let's break down the potential problems and alternative approaches:

Error 1: Unexpected Character

This error likely occurred because you removed the dollar sign ($) from the nextPage URL. Here's why:

Dollar signs ()areoftenusedwithinURLstorepresentdynamicvalues.Removingitmighthavecausedunexpectedparsingbehavior.∗∗Solution:∗∗−∗∗Keepthedollarsign():** Don't remove the dollar sign from the nextPage URL. It's likely part of a valid parameter within the URL.

Error 2: Invalid Pagination Rule

This error indicates an issue with the way you're constructing the final URL with the appended fields. Here are some possibilities:

Extra Space: There might be an extra space before the ampersand (&) in your configuration nextPage & "&fields=...".

Solution:

Double-check for spaces: Ensure there are no extra spaces before the ampersand (&) in your configuration string.

Invalid Characters: Some special characters might not be allowed within URLs. Check the documentation for your specific API to see if any characters in your fields parameter are restricted.

Solution:

Review API documentation: Refer to the API documentation to see if any characters within your fields parameter need to be escaped or encoded for URL usage.

Here are some alternative configuration approaches you can try:

Use a Function:

Instead of directly modifying the nextPage parameter, use a function to construct the final URL. This approach offers more control over string manipulation.

Here's an example using the concat function:

"queryParameters": { "fields": { "value": "@concat(nextPage, '&fields=title,start_date,last_modified')" } }

Use a Template:

Define a template for the final URL that includes placeholders for nextPage and the fields parameter.

Here's an example using a template:

"queryParameters": { "fields": { "value": "@{template('https://{nextPage}&fields={fields}')}" } }, "parameters": { "nextPage": { "type": "string" }, "fields": { "type": "string", "defaultValue": "title,start_date,last_modified" } }

Remember to replace title,start_date,last_modified with your actual desired fields.

By trying these different approaches and carefully reviewing the error messages, you should be able to identify the root cause of the issue and configure your pagination rule correctly.
phemanth 15,755 Reputation points Microsoft External Staff Moderator

2024-06-06T09:54:19.48+00:00
@max teitelbaum

Thank you for asking. Here is the clear explanation from my previous response

1. Pipeline Structure:

Source: Set up your source activity to retrieve the initial data from the API. This could be a Web Activity or any other relevant source connector in ADF.

Data Transformation (Optional): You can include a Data Flow activity if you need to transform the data before pagination.

Sink: Define a sink activity to store the final paginated data. This could be an Azure Data Lake Storage (ADLS), Azure SQL Database, or any other supported destination.

Loop: Use a For Each activity to iterate through the paginated responses.

2. Pagination Rule Configuration:

Within the loop activity, configure the pagination rule for the Web Activity (or your source activity) that retrieves data from the API. Here's how:

Activity Properties: Go to the properties of your Web Activity (or source activity).

Settings: Under the settings tab, locate the Pagination section.

Pagination Type: Choose Next Link (assuming the API response provides a URL for the next page in a field).

Next Link Field: Specify the name of the field in the response that contains the URL for the next page. In your case, it's nextPage.

Items: Set the value for the Items property to an empty array []. This will be used to store the final paginated data.

3. Web Activity (or Source Activity) Script:

Within the Web Activity (or source activity) script, modify the query parameters to include the desired fields using the absolute URL method with "&" concatenation. Here's an example using

# Import libraries (if needed) import json # ... your existing code to call the API and get the response # Access the nextPage URL from the response next_page_url = response.json().get('nextPage') # Construct the final URL with appended fields fields = 'title,start_date,last_modified' final_url = next_page_url + f"&fields={fields}" # Update the request details with the final URL activity.url = final_url # ... rest of your code to process the response data

4. Loop Logic:

Inside the For Each activity loop, use a Set Variable activity to append the retrieved data from each iteration to the Items array defined earlier. Here's an example:

Set Variable Activity: Name: paginatedData (or any preferred name) Value: @concat(variables('Items'), activity('Web Activity').output.value)

This will concatenate the existing data in the Items array with the new data retrieved from the current iteration of the loop through the Web Activity.

5. Sink Activity Configuration:

Configure your sink activity to write the final paginatedData array containing all the paginated data to the desired destination.

Remember to replace the placeholders like fields with your actual desired fields and modify the script based on your specific programming language and API call detailsyour specific programming language and API call details.

1 answer

Your answer

phemanth 15,755 Reputation points Microsoft External Staff Moderator

2024-05-10T08:14:26.5066667+00:00

@Max Teitelbaum

Thanks for using MS Q&A platform and posting your query.

The issue with your current pagination rules configuration is that you are using the plus sign (+) for concatenation, which is incorrect for URLs.

To fix this, you should use URL concatenation. URL concatenation uses an ampersand (&) to join multiple parameters together in a query string. For example:

https://api-prod.livegroup.co.uk/event/list?page_number=1&page_size=10&fields=title,start_date,last_modified

In your current configuration, you are setting the value of the fields parameter to be nextPage + "&fields=title,start_date,last_modified". This would result in a query string that looks like:

https://api-prod.livegroup.co.uk/event/list?page_number=1&page_size=10&fields=https://api-prod.livegroup.co.uk/event/list?page_number=2&page_size=10&fields=title,start_date,last_modified

This Might not work because the fields parameter is now set to the entire value of the nextPage parameter, rather than the string you want to append.

To fix this, you should modify your query parameter to use URL concatenation instead of the plus sign. Here is the corrected code:

Query Parameter: Set to modify fields with the value nextPage & "&fields=title,start_date,last_modified"

This will correctly concatenate the &fields=title,start_date,last_modified string to the nextPage URL

Hope this helps. Do let us know if you any further queries.
phemanth 15,755 Reputation points Microsoft External Staff Moderator

2024-05-13T05:57:35.61+00:00

@Max Teitelbaum We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
Max Teitelbaum 0 Reputation points

2024-05-28T05:28:17.8866667+00:00

Hello,

Thank you for your suggestion regarding the issue with the pagination rules configuration. I understand that using an ampersand (&) for URL concatenation is the correct approach here.

However, I'm a bit unsure about the absence of query parameters because it seems that the 'fields' will still need to be concatenated as a string. Also, if we're relying on the nextPage field from the body, it suggests that the base URL is already provided, allowing us to append additional parameters directly.

So, to clarify, are you suggesting we use the absolute URL method and directly append our string with nextPage & "&fields=title,start_date,last_modified"? This approach does seem straightforward as long as nextPage includes the necessary base URL.

Thanks again, and I look forward to your clarification to ensure I'm on the right track.

Best regards,

Max
phemanth 15,755 Reputation points Microsoft External Staff Moderator

2024-05-28T09:31:48.11+00:00

@Max Teitelbaum

Your understanding of the situation is spot on. Here's a breakdown of your points:

Concatenating fields: You're correct that the "fields" parameter still needs to be included as a comma-separated string, even when using the absolute URL method.

nextPage and base URL: Yes, the assumption is that the "nextPage" field within the response body already provides the complete URL, including the base URL and any existing query parameters. By appending "&fields=title,start_date,last_modified" to "nextPage", you're essentially adding the "fields" parameter to the existing URL.

So, if your "nextPage" response looks something like this: "nextPage": "https://api.example.com/data?limit=10&offset=20" Then, appending the fields parameter would be: "https://api.example.com/data?limit=10&offset=20&fields=title,start_date,last_modified"

This approach simplifies the code and avoids the need for manual base URL construction, as long as the "nextPage" field reliably provides the complete URL.

In summary, using the absolute URL method with "&fields=title,start_date,last_modified" appended to "nextPage" is the correct approach, assuming the provided URL includes the base URL and any existing query parameters.
Max Teitelbaum 0 Reputation points

2024-05-31T18:07:37.13+00:00

I've attempted to implement your suggested approach using several combinations, but unfortunately, I encountered some errors. Below are the details of the issues I faced:

The first error message indicated a failure on the 'Source' side with a specific error code relating to a failure in reading from a REST resource. The error message suggested an unexpected character issue in the parsing path. : "Failure happened on 'Source' side. ErrorCode=RestResourceReadFailed,'Type=Microsoft.DataTransfer.Common.Shared.HybridDeliveryException,Message=Fail to read from REST resource.,Source=Microsoft.DataTransfer.ClientLibrary,''Type=Newtonsoft.Json.JsonException,Message=Unexpected character while parsing path: ,Source=Newtonsoft.Json,'"

After modifying the nextPage parameter by removing the dollar sign, I encountered a different error. This time, the system reported an invalid pagination rule, again failing on the 'Source' side:

It errors out: Failure happened on 'Source' side. ErrorCode=RestInvalidPaginationRule,'Type=Microsoft.DataTransfer.Common.Shared.HybridDeliveryException,Message=Invalid PaginationRule, RuleKey='AbsoluteUrl', RuleValue='nextPage & "&fields=attendee_id,first_name,last_name,company,attendance_Status,delegate_Type,email,last_modified,registration_date"',Source=Microsoft.DataTransfer.ClientLibrary,'

Could you or anyone else suggest any alternative configurations that might resolve these issues? I'm eager to find a solution and would greatly appreciate any further assistance you can provide.

Answer 1

Max Teitelbaum 0

thanks for your response, can you provide me with an actual example of a pipeline with screenshots of your implementation? I'm not able to understand your approach.

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Azure Data Factory pagination using QueryParameters and body field

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