RepositoryFileApi fails to upload large files (10MB+) due to application/x-www-form-urlencoded encoding

[heyuqiang]

Description

When using RepositoryFileApi.createFile() or updateFile() in GitLab4J to upload a Base64-encoded file (~10MB ZIP), the request fails with HTTP 400.

Directly calling the GitLab API via curl with Content-Type: application/json works correctly.

Steps to Reproduce

Prepare a ZIP file test.zip (~10MB).

Use GitLab4J RepositoryFileApi to upload it as Base64 content:

RepositoryFile file = new RepositoryFile();
file.setFilePath("test.zip");
file.setContent(base64Content);
file.setEncoding(org.gitlab4j.models.Constants.Encoding.BASE64);

RepositoryFileApi fileApi = gitLabApi.getRepositoryFileApi();
fileApi.createFile(projectId, file, "main", "add test.zip");

The API returns HTTP 400 Bad Request.

The server logs show (Rails / Workhorse):

{
"status":400,
"written_bytes":11,
"method":"PUT",
"uri":"/api/v4/projects/2/repository/files/test.zip",
"backend_id":"rails"
}

Using curl works:

curl --request POST
--header "PRIVATE-TOKEN: $TOKEN"
--header "Content-Type: application/json"
--data '{
"branch": "main",
"commit_message": "add test.zip",
"content": "",
"encoding": "base64"
}'
"$GITLAB_URL/api/v4/projects/$PROJECT_ID/repository/files/test.zip"

Analysis

The GitLab4J post(Form formData, URL url) method sends the request as:

Entity.entity(formData.asMap(), MediaType.APPLICATION_FORM_URLENCODED_TYPE)

That is, the request uses application/x-www-form-urlencoded instead of application/json.

For large Base64 files, Rails cannot parse the form-encoded body → 400.

Small text files may succeed, which is why this only occurs for large files.

Expected Behavior

RepositoryFileApi should correctly upload large Base64 files (>10MB) using JSON requests.

Or GitLab4J should document the limitation and recommend using Project Upload API for large binary files.

Environment

GitLab4J version: 6.1.0

GitLab server version: gitlab-ce 18.3.0

Java version: jdk21

Suggested Solutions

Change RepositoryFileApi to send JSON with Content-Type: application/json.

Alternatively, clearly document that large binary files should use ProjectApi.uploadFile().

[heyuqiang]

CommitPayload payload = new CommitPayload();
payload.setBranch("main");
payload.setCommitMessage("add dict1j.zip");
CommitAction action= new CommitAction();
action.setAction(CommitAction.Action.CREATE);
action.setFilePath("dict1j.zip");
action.setContent(content);
action.setEncoding(Constants.Encoding.BASE64);
payload.withAction(action);

Commit commit = gitLabApi.getCommitsApi().createCommit(28, payload);
System.out.println(commit.toString());