CODEWITHSUNDEEP
pythonpython-requeststrello
Lux
Lux

Reputation: 353

Trello API - 400: "Error parsing body" when POSTing a multipart file attachment

I'm trying to upload a PDF as an attachment to a Trello card using python-requests. I've been unable to get the request in the function below to return anything other than 400: Error parsing body despite significant tweaks (detailed below).

I should note that I'm able to create cards and add URL attachments to them (neither of which require a file upload) without any problems.

Here's the code that handles the POST of the file:

def post_pdf(session, design, card_id):
    attachment = {
            "name": design["campaign_title"] + " - Combined PDF",
            "mimeType": "application/pdf"
        }
    pdf_post = session.post(
        url = "https://api.trello.com/1/cards/" + card_id + "/attachments",
        files = {"file": open("combined_pdf.pdf", "rb")}, 
        data = attachment
    )

The authentication key and token are set Session params when the session was created, so they're not added here.

Also, in the actual code, the POST is handled by a wrapper function that adds some boilerplate error-checking and rate limiting to the request, as well as more-verbose error dumps when a request fails, but I've confirmed (in the above example) that the same error persists without the wrapper.

Adjustments I've tried

Note: The PDF file is potentially a source of the problem - it's generated by converting several images to PDF format and then concatenating them with pdfunite, so I could well have made mistakes in its creation that are causing Trello to reject the file. What seems to confirm this is that Googling for Trello "Error parsing body" returns two hits, only one of which deals with Trello, and neither of which are useful. This leads me to think that this is a particularly odd / rare error message, which means to me that I've made some kind of serious error encoding the file.

However, the PDF file opens properly on my (and my coworkers') systems without any error messages, artifacts, or other strange behavior. More importantly, trying this with other "known good" PDFs also fails, with the same error code. Because the file's contents fall within the bounds of "company property / information", I'd like to avoid posting it (and / or the raw request body), but I'll do so if there's agreement that it's causing the problem.

Upvotes: 2

Views: 3338

Answers (1)

Lux
Lux

Reputation: 353

I found the solution: the Content-Type header was set incorrectly due to a session-wide setting ( Session.headers.update({"Content-Type": "application/json"}) ) overriding the multipart/form-data header when the upload request was sent. This caused Trello to reject the body. I solved the problem by removing the session-level header, which allowed requests to modify the content type for each request.

Upvotes: 3

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