[Bug]: $after querystring parameter gets added multiple times

[cdgipson]

What happened?

Ran the initial request with ?$first=5.

http://localhost:5000/api/StaffType?$first=5

Then ran the next link, it only contained one $first and one $after.

http://localhost:5000/api/StaffType?$first=5&$after=W3siRW50aXR5TmFtZSI6IlN0YWZmVHlwZSIsIkZpZWxkTmFtZSI6IklkIiwiRmllbGRWYWx1ZSI6OSwiRGlyZWN0aW9uIjowfV0=

The following nextLink contained two $after parameters.

http://localhost:5000/api/StaffType?$first=5&$after=W3siRW50aXR5TmFtZSI6IlN0YWZmVHlwZSIsIkZpZWxkTmFtZSI6IklkIiwiRmllbGRWYWx1ZSI6OSwiRGlyZWN0aW9uIjowfV0%3D&$after=W3siRW50aXR5TmFtZSI6IlN0YWZmVHlwZSIsIkZpZWxkTmFtZSI6IklkIiwiRmllbGRWYWx1ZSI6MTcsIkRpcmVjdGlvbiI6MH1d

When you follow that link it results in the following error.

{
"error": {
"code": "BadRequest",
"message": "The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.\n at System.Convert.FromBase64CharPtr(Char* inputPtr, Int32 inputLength)\n at System.Convert.FromBase64String(String s)\n at Azure.DataApiBuilder.Core.Resolvers.SqlPaginationUtil.Base64Decode(String base64EncodedData) in /src/src/Core/Resolvers/SqlPaginationUtil.cs:line 516\n at Azure.DataApiBuilder.Core.Resolvers.SqlPaginationUtil.ParseAfterFromJsonString(String afterJsonString, PaginationMetadata paginationMetadata, ISqlMetadataProvider sqlMetadataProvider, String entityName, RuntimeConfigProvider runtimeConfigProvider) in /src/src/Core/Resolvers/SqlPaginationUtil.cs:line 285",
"status": 400
}
}

I expected the endpoint to return the nextLink only containing one $after parameter, which points to the next set of records based upon the request that generated the response.

Version

0.8.52

What database are you using?

Azure SQL

What hosting model are you using?

Local (including CLI)

Which API approach are you accessing DAB through?

REST

Relevant log output

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[cdgipson]

I evaluated the contents of the two $after parameters. This makes a slight bit of sense to contain info for the current set of data and the next. However, it is still up to the calling application to store previous $after values so that it can page the data in both directions. If we are taking the assumption that the calling app will be doing this, I feel that only the $after data parameter for the next set of records needs to be returned.

[severussundar]

Hey @cdgipson, I'm unable to repro this. In my setup, the nextLink always contains only one $after field (Using the nextLink twice does not lead to the addition of 2 $after fields in the URL.). Also, using the nextLink, I'm able to successfully query until the end of records contained in the entity without hitting any errors. I tried this against table, view and stored procedure; everything seems to work correctly.

Ex:

GET  /api/Book?$first=2

First nextLink ---> https://localhost:5001/api/Book?$first=2&$after=W3siVmFsdWUiOjQsIkRpcmVjdGlvbiI6MCwiVGFibGVTY2hlbWEiOiJkYm8iLCJUYWJsZU5hbWUiOiJib29rcyIsIkNvbHVtbk5hbWUiOiJpZCJ9XQ%3D%3D

Second nextLink ---> https://localhost:5001/api/Book?$first=2&$after=W3siVmFsdWUiOjYsIkRpcmVjdGlvbiI6MCwiVGFibGVTY2hlbWEiOiJkYm8iLCJUYWJsZU5hbWUiOiJib29rcyIsIkNvbHVtbk5hbWUiOiJpZCJ9XQ%3D%3D

One thing to note is that the nextLink generated is a complete URL against which the subsequent GET request can be executed directly (No modifications are needed).

Could you please share more info regarding your setup that leads to this error - your config file, the type of entity, the way you are executing the GET requests, etc.

[seantleonard]

Fixed with #2006 in latest stable release. 0.10.23 https://github.com/Azure/data-api-builder/releases/tag/v0.10.23