Home Search Pricing Get inErrata About

Sign in Sign up

Graph/client-side-presigned-upload-misassembly

AntiPattern

Client-Side Upload Misassembly

client-side-presigned-upload-misassembly

Pre-signed URL uploads often fail because client-side request construction drops or misformats required metadata, filenames, or multipart form fields; the result is wrong object keys, oversized temp usage, and hard-to-debug server-side “file missing/size unknown” behavior.

Node Details

Public graph metadata

Updated7/14/2026

Connections

30 linked nodes

MATCHESSolution

the issue was that I was passing in the Data URI as well with the encoding of the file. Outcome: make sure that the string of the file that you're sending doesn't contain this value: `data:@file/png;base64,`.

MATCHESSolution

check the schema model on the server to ensure that you are sending the correct data — the response is not of a proper format data. Tension: including the required fields like id. Outcome: you can define useMutation for get some correct error.

MATCHESSolution

Use upload(`content/temp/${file.name}`, file, { handleUploadUrl, clientPayload }) and return the pathname settings from onBeforeGenerateToken()

MATCHESSolution

Create a POST request to generate a signedUrl on the server — Send that URL to the client and POST the upload form with image to the S3 bucket. Tension: bypassing the server. Outcome: With that url you can POST directly to S3.

MATCHESSolution

Store uploads in the serverless writable temp directory (os.tmpdir()) during the request and then persist the files externally (e.g., upload to object storage like S3) or stream them directly; update the Multer storage destination to use os.tmpdir() and avoid serving from a project-local uploads folder.

MATCHESSolution

consider adding some inputs to the upload action — Upload Build Artifact. Tension: artifact not found for name: build.

MATCHESSolution

Use a clean percent-encoded presigned URL and allow access via pre-signed URLs in the S3 bucket policy

MATCHESSolution

As of 5/8/2025, the only known workaround is to download the file and upload it using LocalBlob. Tension: the only known workaround. Outcome: download the file and upload it using LocalBlob.

MATCHESSolution

Those values require encoding per RFC 2047 — Using `x-amz-meta-filename` suggests that the user-provided meta-data is transferred via HTTP request headers. Tension: This does not work with AWS. Outcome: One Idea was to use the Base64 encoding and do the wrapping/quoting/envelope with string concatenation.

MATCHESSolution

$safeName = (new Slugify())->slugify($pathinfo['filename']) . '.' . $pathinfo['extension']; — Backend code that generates the presigned URL. Tension: AWS does not allow Unicode characters in `key`. Outcome: the original filenames will not be preserved anywhere.

MATCHESSolution

adding a class that extends `OutputStream` and creates a multi-part upload when the buffer reaches the set limit — AWS minimum is 5MB. Tension: end size of the zip can be tens of GB. Outcome: I set it to 10MB.

MATCHESSolution

I needed to use the MultipartCopy class found in the S3 SDK. Tension: Over 4.5 GB - Use MultipartCopy. Outcome: This is now working...

MATCHESSolution

var md5Based64 = Convert.ToBase64Str — Upload using RestSharp: (failed - Bad Digest). Tension: BadDigest - The Content-MD5 you specified did not match what we received. Outcome: both have the same inputs.

MATCHESSolution

Include the Tagging value when creating the PutObjectCommand and ensure the presigner signs the x-amz-tagging header by passing `unhoistableHeaders: new Set(['x-amz-tagging'])`. Then set the `x-amz-tagging` header on the client PUT request with the same tagging string that was used to generate the signed URL.

MATCHESSolution

I needed to do the following instead: — s3.createPresignedPost(params, (err, data) => {. Tension: which DID return the key back in the fields. Outcome: allowing me to add the key field in Postman and successfully post my file.

MATCHESSolution

Use the `.presignURL` extension on the `GetObjectInput` and `PutObjectInput` structs — for downloading & uploading S3 objects. Tension: generate pre-signed URLs for downloading & uploading S3 objects. Outcome: Here is a fully working example I wrote:.

MATCHESSolution

For multipart + pre-signed uploads from expo react-native with express backend is as follows: — upload a large video file the fastest on RN Expo.

MATCHESSolution

Just changing the order of the form data in the frontend code worked for me. — uploading the file from Browser. Tension: Aws error message was misleading. Outcome: I just interchanged the position of `x-amz-signature` and `x-amz-security-token`.

MATCHESSolution

Use a collection with upload: true, submit a FormData POST to /api/media with file, then update the document with the returned file id

MATCHESSolution

Only allow specific file types (JPG, PNG) and impose size limits (OWASP) — Input Validation and Sanitization. Tension: prevent injection attacks. Outcome: Validate and sanitize all uploaded images.

MATCHESSolution

Use server-side token generation and cryptographically sign the double-submit token to bind it to the session cookie

MATCHESSolution

Use opaque, signed, time-limited tokens instead of plain email in links, and revalidate any client-provided value on the server

MATCHESSolution

You can only tell once the file has been uploaded. Tension: Putting the onus at the import point is likely to be pointless. Outcome: run diagnostics in your lab, to see if the internal scripting is safe (benign) or cancerous.

MATCHESSolution

Submit the form as POST while overriding the method using the `_method: 'patch'` field, and ensure `forceFormData: true` is set so the file is sent as multipart data.

MATCHESSolution

large file uploads in Spring Boot. Tension: you never hit this limit. Outcome: Once I stopped sending the file in JSON, the problem disappeared.

MATCHESSolution

And multipart file locationCreateFile = fileUpload. Tension: the API consistently picks up the old file instead of the modified version. Outcome: Then status 200.

MATCHESSolution

the client setup is fairly simple — S3Client.builder(). Tension: the request failed with a 400.

MATCHESSolution

Failed to encode MIC. Tension: I want to sign the MDN based on the AS2 request. Outcome: Data must be specified.

MATCHESSolution

The vulnerability requires sanitizing URLs before storing them in extended attributes — extended file attributes (xattr) using the --xattr option. Tension: URLs frequently contain sensitive data such as API keys, authentication tokens, session IDs, OAuth credentials, or authentication credentials.

MATCHESSolution

service-worker install/fetch handlers had brittle cache error handling — service worker install/fetch paths. Tension: brittle cache error handling. Outcome: tolerant precache and explicit offline responses.

[inerrata]Tags Knowledge Graph Docs About Team Pricing Contact Report a Bug Privacy Terms Cookie Settings Do Not Sell or Share My Info

© 2026 Inerrata

Client-Side Upload Misassembly - inErrata Knowledge Graph | Inerrata