Trouble Authorizing API Request to Download Attachment

Question

I have read a number of threads on downloading attachments using the API, including the "Update: Authenticated Access to S3," but have not been able to download an attachment successfully.

I am using Postman for my testing and the following URL to get the download:

https://api.trello.com/1/cards/{{trello_card_id}}/attachments/{{trello_attachment_id}}/download/{{trello_attachment_filename}}

I have added the following header:

Authorization: OAuth oauth_customer_key="{{trello_api_key}}", oauth_token="{{trello_api_token}}"

I am getting a 401 Unauthorized response with a text message of "invalid app key"

I have checked the console to verify that the request is accurately formatted (or at least looks ok)

GET https://api.trello.com/1/cards/5e9***a2c/attachments/672***79a/download/koala.png

Request Headers:
Authorization: OAuth oauth_customer_key="e5a***974", oauth_token="ATT***BEB"

I have confirmed that the {{trello_card_id}} and {{trello_attachment_id}} as well as {{trello_api_key}} and {{trello_api_token}} are accurate by successfully requesting...

https://api.trello.com/1/cards/{{trello_card_id}}/attachments/{{trello_attachment_id}}?key={{trello_api_key}}&token={{trello_api_token}}

NOTE: I am using a manually generated token.  I have tried creating a new API key and associated manual token, but with the same results.

I am sure I have a typo or missed something from the instructions.  Any suggestions/help is greatly appreciated!!!

Thank You.

ROB

Rob Banning · Answer

Thank you for your ideas...  I tried your first three suggestions but could not get them to work.  (same errors)

I just finished building an ASP.NET Core Web API with your NuGet package and tested the following methods with three different KEY/TOKEN pairs (on two different accounts)

* GetBoardsCurrentTokenCanAccessAsync
* GetCardsOnBoardAsync
* GetCardAsync
* GetAttachmentsOnCardAsync
* GetAttachmentOnCardAsync
* DownloadAttachmentAsync

ALL WORKED !!! (esp. the Download)

I will try an alternative to Postman to see if that might have been the problem.  I will report back.

BTW - I really like your TrelloDotNet package.  I have something similar in one of my ASP.NET Core Web API services, but certainly not as exhaustive and elegant.  It's time to refactor my API service to incorporate your package.  THANK YOU.

ROB

Rasmus Wulff Jensen · Answer

Hmm, running out of ideas here:

* Could you try while logged into Trello with account that own the key, and try to go directly to the download url in the browser (you should be able to get it that way)
* Try to generate a new api key/token (https://m.youtube.com/watch?v=ndLSAD3StH8) to check if they are somehow semi broken
* Try another board with another card/attachment
* Try the C# Lib mentioned (if you know C#)
* Try alternative to Postman (if some odd config in postman cause this)

If all above fail I can also try to make a small addition to my https://trellotools.azurewebsites.net/ with an interface to test it out (been meaning to build a sandbox API test for a long time but never got around to do it)

Rob Banning · Answer

NOTE - I was working with a KEY and TOKEN from my ("free") test Trello account.  Just to be sure there wasn't something an issue associated with this test account, I tried everything with a KEY and TOKEN from my premium account (updating the card and attachment ids, too).  I got the same results:  The JSON requests with the KEY and TOKEN pass in the query params works fine.  The issue is with my Authorization header.