java.io.IOException: Server returned HTTP response code: 400 for URL:

Question

I am doing a GET request and this code, which works for all of our existing tests, is giving 400 error for a new endpoint. I can hit the endpoint fine in postman. conn.getErrorStream() doesn't print out anything. The code seems to fail (without throwing exception)right at url.openConnection. If I do conn.getResponseCode() right after that line it returns 400. I thought perhaps it wasn't liking the pipe char I have in my query but encoding it via URLEncoder.encode(resourceContext) as well as URLEncoder.encode(baseUrl + resourceContext) didn't help and ended up throwing MalformedURLException. Here is the endpoint I want to hit (anonymized): https://usqa0003d.usa.company.com:17462/positions/1535000400000/CUR/USA|415|415|CUST|GL53I7TPYBYM|MATCHED

When I attach the debugger to the server I want to hit nothing happens so the request never makes it to the server. I step into openConnection which leads to a rabbit hole full of var5, var6 etc. I switched to HttpsURLConnection but no dice there either. Any other suggestions?

URL url = new URL(baseUrl + resourceContext);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setDoOutput(true);
        conn.setRequestMethod(requestType);
        if(messageLibraryJson) {
            conn.setRequestProperty("Content-Type", "application/json;class=true");
            conn.setRequestProperty("Accept", "application/json;class=true");
        } else {
            conn.setRequestProperty("Content-Type", "application/json");
            conn.setRequestProperty("Accept", "application/json");
        }

        String userpass = username + ":" + password;
        String basicAuth = "Basic " + javax.xml.bind.DatatypeConverter.printBase64Binary(userpass.getBytes());
        conn.setRequestProperty("Authorization", basicAuth);

        if(requestType.equals("POST")) {
            OutputStream os = conn.getOutputStream();
            os.write(requestJson.getBytes());
            os.flush();
        }

        if (conn.getResponseCode() != HttpURLConnection.HTTP_OK) {
            logger.error("ERROR in REST CLIENT");
            logger.error("URL = " + baseUrl + resourceContext);
            logger.error("Request = " + requestJson);
            throw new RuntimeException("Failed : HTTP error code : "
                    + conn.getResponseCode());
        }

        BufferedReader br = new BufferedReader(new InputStreamReader(
                (conn.getInputStream())));

Answer 1

Indeed it was the '|' char causing trouble. If I do the following:

        String urlString = (baseUrl + resourceContext).replace("|", "%7C");
        URL url = new URL(urlString);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();

It works. The following urlString is produced: https://usqa0003d.usa.company.com:17462/positions/1535000400000/CUR/USA%7C415%7C415%7CCUST%7CGL53I7TPYBYM%7CMATCHED

However, when I do:

String enc = baseUrl + URLEncoder.encode(resourceContext);

I get: https://clqa0003d.usa.company.com:17462/positions%2F1535000400000%2FCUR%2FUSA%7C415%7C415%7CCUST%7CGL53I7TPYBYM%7CMATCHED

The '/' is replaced by '%2F' (in addition to the pipe char) and for some reason that causes trouble. For reference, the endpoint is actually defined as such:

@RequestMapping(value = "/{param1}/{param2}/{param3:.*}", method = RequestMethod.GET)

With the class level endpoint (how is that called???) as:

@RequestMapping(value = "/positions",
    produces = {"application/vnd.cme.cdo+json", "application/json;class=true", "application/x-protobuf", "application/x-protobuf-text"},
    consumes = {"application/vnd.cme.cdo+json", "application/json;class=true", "application/x-protobuf", "application/x-protobuf-text"})
public class PositionController implements IPositionController {

Can anyone comment on why converting '/' to '%2F' causes trouble?