davethecross davethecross - 2 months ago 26
Ajax Question

Losing information when uploading large base64 image through POST request

I am attempting to upload an image string(base64) and save it as an image server side.

The issue is that when I upload a large image(1200 px width jpg full quality) I lose some information as it's uploading.

My code works though because smaller images upload and save just fine.

I have already checked my ini php file and have max filesize upload and max post high enough that it really shouldn't be the issue (40 m).

My information gets passed along like this:

  • get base64 image data from phone camera (works, can display image client side)

  • place image data into a hidden form field (no information lost at this point)

  • send data through ajax POST request (no bugs or anything)

  • receive the image string from php POST variable (This is where I lose the information)

-- strlen before upload: 5,253,100

-- strlen after upload: 524,288

  • save image by using base64_decode (works fine, saves smaller images properly)

Now when I upload a larger image, I don't get any errors. The code still spits out a picture, but the picture is just the top quarter or so of the original image with the rest being grey.

I'd post some of my code but I'm fairly confident it isn't in my code since everything was working perfectly till I upped my image size. I am definitely losing the information at some point during the POST request.

Any tips to point me in the right direction would be lovely. Thanks for reading.


I've found the solution. It turns out that my data was getting cut off when I placed it inside a textbox. I didn't know textboxes had a maximum limit but in my case the textbox was truncating my data at 524288 characters.