JSON API דרך curl

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A user is trying to use the JSON API via curl from Java to add a user to a group on Discourse, but receives a 400 Bad Request error. The issue occurs when executing curl from Java, though the same command works in the terminal. cookieman768 shares their Java code, which constructs the curl command with proper headers and JSON data. amotl suggests checking the command string and questioning the quoting and JSON formatting. After trying variations, including removing spaces in the JSON key and testing with usernames without special characters, the problem persists. amotl proposes removing the space in the JSON key, but cookieman768 concludes that the issue may lie in the Java execution environment and plans to use a library instead.

1

So, I’m using the JSON API to add a user to a group, it works as expected when I used the terminal but when I’m calling curl from Java I’m getting {"status":400,"error":"Bad Request"}

So, I looked in the logs and saw:
image

Does anyone know what I’m doing wrong?

2

Hi there,

most probably, the arguments to curl (I assume you are shelling out from Java) are not forwarded correctly. This is often related to incorrect quoting.

If you share the corresponding Java code here, people might be able to guess what might be going wrong.

With kind regards,
Andreas.

3

Totally! Here’s what I have so far:

command = "curl -X PUT https://discourse.domain.tld/groups/" + roleID + "/members.json \\\n" +
                    "     -d \'{\"usernames\" : \"" + user.get("username") + "\"}\'\\\n" +
                    "     -H \"Content-Type: application/json\"\n" +
                    "     -H \"Accept: application/json\"\n" +
                    "     -H \"Api-Key: redacted\"\\\n" +
                    "     -H \"Api-Username: Bot\"";
Process nitroProcess = Runtime.getRuntime().exec(command);
            String outputString = new BufferedReader(
                    new InputStreamReader(nitroProcess.getInputStream(), "UTF-8"))
                    .lines()
                    .collect(Collectors.joining("\n"));
            System.out.println("Output String: " + outputString);

I’m passing an integer for the roleID and user.get("username") is just a String from a JSON request.

I can post more if it would help, but I am trying to be careful to not leak any sensitive information.

4

Can you System.out.println(command) and share the output, with the content of the variables roleID and user.get("username") redacted, if appropriate?

With kind regards,
Andreas.

5

I am not sure if quoting \' is correct. What about this?

-d '{\"usernames\": \"" + user.get("username") + "\"}'\\\n"

6

So, my CURL command looks like:

curl -X PUT https://discourse.domain.tld/groups/50/members.json \
     -d '{"usernames" : "Torbjörn"}'\
     -H "Content-Type: application/json"
     -H "Accept: application/json"
     -H "Api-Key: [redacted]"\
     -H "Api-Username: Bot"

As far as the quoting goes, I was following the docs here.

If I paste that command in my WSL terminal it runs and works as intended.

7

Thank you. I want to note that some lines end with \ and some not. Also, might the Umlaut have the chance to be the culprit here? Can you also test it with a username without an Umlaut?

8

I removed the \ from some lines because it was throwing a different error. When I have a username without any special characters, it’s the same issue.

curl -X PUT https://discourse.domain.tld/groups/50/members.json \
     -d '{"usernames" : "Av3r4ge"}'\
     -H "Content-Type: application/json"
     -H "Accept: application/json"
     -H "Api-Key: [redacted]"\
     -H "Api-Username: Bot"
Output String: {"status":400,"error":"Bad Request"}
{"error":"Bad Request","status":400}
9

I am out of ideas here.

Maybe, while it should still be valid JSON, can you remove the space after the key for the JSON payload, like this:

{"usernames": "Av3r4ge"}
10

Yeah, same issue - at this point, I’m most likely going to look into using a library for doing the request. I just have no idea why it’s being so difficult. Thank you for helping me troubleshoot.