CODEWITHSUNDEEP
pythongoogle-app-engineblobstore
marcorossi
marcorossi

Reputation: 2011

Google App Engine: upload file and other fields in the same request

I want to upload an image to the blobstore, because I want to support files larger than 1MB. Now, the only way I can find is for the client to issue a POST where it sends the metadata, like geo-location, tags, and what-not, which the server puts in an entity. In this entity the server also puts the key of a blob where the actual image data is going to be stored, and the server concludes the request by returning to the client the url returned by create_upload_url(). This works fine, however I can get inconsistency, such as if the second request is never issued, and hence the blob is never filled. The entity is now pointing to an empty blob.

The only solution to this problem I can see is to trigger a deferred task which is going to check whether the blob was ever filled with an upload. I'm not a big fan of this solution, so I'm guessing if anybody has a better solution in mind.

Upvotes: 0

Views: 94

Answers (1)

tx802
tx802

Reputation: 3564

I went through exactly the same thought process, but in Java, and ended up using Apache Commons FileUpload. I'm not familiar with Python, but you'll just need a way of handling a multipart/form-data upload.

I upload the image and my additional fields together, using JQuery to assemble the multipart form data, which I then POST to my server.

On the server side I then take the file and write it to Google Cloud Storage using the Google Cloud Storage client library (Python link). This can be done in one chunk, or 'streamed' if it's a large file. Once it's in GCS, your App Engine app can read it using the same library, or you can serve it directly with a public URL, depending on the ACL you set.

Upvotes: 1

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