Develop Reference

Upload file using java MultipartEntityBuilder throws Content too long. What's an alternative?

I'm trying to make a little utility that will synchronise data between two servers. Most of the calls there are REST calls with JSON, so I decided to use Apache HttpClient for this.
There is however a section where I need to upload a file. I'm trying to do this using the mutipart form data with the MutipartEntityBuilder but I encounter a Content too long problem. (I tried to gzip the contents of the file too, but I'm still going over the limit).
Here's my java code:
HttpPost request = new HttpPost(baseUrl+URL);
MultipartEntityBuilder builder = MultipartEntityBuilder.create();
//create upload file params
builder.addTextBody("scanName", "Test upload");
builder.addBinaryBody("myfile", f);
HttpEntity params= builder.build();
request.setEntity(params);
request.addHeader("content-type","multipart/form-data");
HttpResponse response = httpClient.execute(request);
Are there better atlernatives that I should be using for the file upload part? I'm also going to download the files from one of the server. Will I hit a similar issue when try to handle those responses?
Is there something I'm doing wrong?

I try to use your code and send some file with size something about 33MB and it was successful. So, I think your problem one of the follows:
Created http client has limitations for request size - in this case you need to change properties of client or use another client;
In some peace of code you call HttpEntity.getContent() method. For multipart request for this method exists limitations - 25kB. For this case you need to use writeTo(OutputStream) instead of getContent()
In comments you told about swagger, but I don't understand what does it mean. If you use swagger generated api, that problems maybe occurred at their code and you need to fix generation logic (or something like this - I never used swagger)
I hope my answer will help you

How to send a SAML Request?

i want to send a SAML request to my IDP (Azure AD) but ia m not sure how to send the request at all.
First i used OpenSAML to build an AuthRequest. Which i encoded as a String.
Now i wanted to use ApacheHttpClient to send the request and read the response and i am not sure if OpenSAML provides http sending methods at all so my idea was to use Apaches HttpClient for this for now.
String encodedAuthRequest = generateAuthRequest();
String url = "http://myidp/samlendpoint";
CloseableHttpClient client = HttpClientBuilder.create().build();
HttpGet request = new HttpGet(url);
// add request header
request.addHeader("User-Agent", USER_AGENT);
// what is to add else?
HttpResponse response = client.execute(request);
I am stuck now since i am not sure how to setup the request, does it need to be a query parameter like ?saml=.... in GET or do i have to put the encoded saml response in the body as POST..
Can someone help or clarify these issue?
Update from Guillaumes answer:
I have this from the IDPs MetaData:
<IDPSSODescriptor>
<SingleSignOnService
Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect"
Location="https://myidp/saml2" />
<SingleSignOnService Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST"
Location="https://myidp/saml2" />

Depends on which binding you are supposed to use. The IdP documentation or metadata should mention that. There are several:
Redirect Binding (using a GET), by far the most common for Requests
POST Binding
Artifact Binding (more complex, but I have never seen it used for Requests)
...
I suppose that Redirect Binding will be used in your case (EDIT: you added the metadata from your IdP, it mentions that you can use both Redirect and POST bindings). It is described here: https://docs.oasis-open.org/security/saml/v2.0/saml-bindings-2.0-os.pdf page 15.
Short version: your must first use the DEFLATE algorithm to compress your XML Request, encode it using base64, encode it using URL encoding, then pass it as a query parameter named SAMLRequest
?SAMLRequest=<your url-encoded base64-encoded deflated authnrequest>
https://en.wikipedia.org/wiki/SAML_2.0#SP_Redirect_Request.3B_IdP_POST_Response

Send xml as part of URL request in Java

This might be a trivial question but I'm trying to send web request to USPS to get a http post response (or email response depending on my request) containing the tracking information based on the tracking number that I send in. The documentation says the xml needs to appended as part of the url like below
http://secure.shippingapis.com/ShippingAPITest.dll?API=TrackV2&XML=<PTSEmailRequest USERID="xxxxx"><TrackId>xxxxx</TrackId><RequestType>EN</RequestType></PTSEmailRequest>
I saw there were 2 ways to make an xml request, one using HttpPost and the other URLConnection. I'm a bit thrown by how I go about this and I'm failing to appreciate what's the difference between appending xml in the url and a normal http request. Can someone please clear things up for me?
USPS documentation for tracking =>
https://www.usps.com/business/web-tools-apis/track-and-confirm.pdf
I read these related Stackoverflow posts
Java: How to send a XML request?
posting XML request in java
HttpClient httpclient = HttpClients.createDefault();
HttpPost httppost = new HttpPost("http://secure.shippingapis.com/ShippingAPITest.dll");
List<String> params = new ArrayList<String>(2);
params.add(new BasicNameValuePair("API", "TrackV2"));
params.add(new BasicNameValuePair("XML", FuncTOGenerateXML()));
httppost.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream instream = entity.getContent();
//.....
// .....
instream.close();
}

An HTTP request can use one of several methods, like POST, GET, DELETE, PUT... Here we talk about POST and GET
Technical differences
With GET, the data is retrieved from the parameters in the URL.
With POST, the data is retrieved from the data transmitted inside the HTTP message.
Intended use differences
GET is intended to be used when the request does not cause a change (v.g., searching in Google). Since you can repeat the request without side effects, the data is in the URL and can be stored in the browser history, favorites, etc.
POST is intended to use when you are performing a change (v.g. sending an e-mail, doing a on-line purchase). The data related is not stored with the URL (it is then that, if you go back to a page that was obtained using POST, the browser many times will show you a pop-up asking for permission to send the data again.
In real usage, the distinction is not so clear cut, in particular POST is sometimes used when the data is too large (URLs have limited length). Also, sometimes GET is used with the meaning of POST so the data can be presented as an HTML link.
Finally, URLConnection is the basic API for opening a connection (which you can use as a POST or GET request, based in how you pass the data, or something else) and HttpPost is just a higher level API for creating a POST request. If you go the basic way, use HttpURLConnection better.

google-http-java-client json update existing object

i'm trying to use google-http-java-client on android and parse JSON responses from my server.
do do that i'm using the following code (provided by the examples of the project)
private static final HttpTransport HTTP_TRANSPORT = AndroidHttp.newCompatibleTransport();
private static final JsonFactory JSON_FACTORY = new JacksonFactory();
HttpRequestFactory requestFactory = HTTP_TRANSPORT
.createRequestFactory(new HttpRequestInitializer() {
#Override
public void initialize(HttpRequest request) {
request.setParser(new JsonObjectParser(JSON_FACTORY));
}
});
HttpRequest request = requestFactory.buildGetRequest(new GenericUrl(url + paramsList));
HttpResponse response = request.execute();
and everything works fine for new objects with
result = response.parseAs(PxUser.class);
but i need to update an existing object with the data from the json string.
with jackson only i can use the following code but with the google client i cannot find any solution.
InputStream in = -get-http-reponse-
ObjectMapper mapper = new ObjectMapper();
ObjectReader reader = mapper.readerForUpdating(MySingleton.getInstance());
reader.readValue(InputStream in);
so i need a way to update an existing object just like with this jackson example but by using the client.
is there a way? do i have to use jackson-databind.jar? how can i accomplish this?
thanks in advance
PS: i can switch to gson if its needed, no problem

It depends on whatever endpoint is receiving the API call, and what it expects the request to look like.
The Google HTTP Java Client simply handles the processes like making the call, encoding and decoding an object, exponential backoff, etc for you. It's up to you to create the request that does what you want and how the server expects it to look.
Likely, the API you're making the request to expects an object update to be made with a PUT request. The updated object is likely going to be the content of the request, encoded in some specific format. Let's assume JSON, since you're parsing JSON responses. So for the purpose of example, let's say you're going to request an object, modify it, then send it back.
First, you get the resource and parse it into your object:
PxUser myUser = response.parseAs(PxUser.class);
Then you modify the object somehow
myUser.setName("Frodo Baggins");
Now you want to send it back to the server as a JSON object in a PUT request:
// httpbin.org is a wonderful URL to test API calls against as it returns whatever if received.
GenericUrl url = new GenericUrl("http://httpbin.org/put");
JsonHttpContent content = new JsonHttpContent(new JacksonFactory(), myUser);
HttpRequest request = requestFactory.buildPutRequest(url, content);
HttpResponse response = request.execute();
System.out.println(response.parseAsString());
The specifics of how you encode and update your content is totally up to you and the API's specification. This is especially easy if you're creating the server receiving the call too.
If you're working with a preexisting API, you may want to update the question with the
specific problem (API "x" requires a response that looks like Blah; how do I do that in the google-http-java-client).
If you're working with a Google API, you'll want to be using the google-api-java-client which does all of this work for you.

How to send "parameters" to all HTTP request methods?

I'm trying to write a Java client (with Apache HttpClient) for the Gengo API which makes use of HTTP GET, POST, PUT and DELETE. However for every RESTful API "method" that they expose, you must pass your API key and signature as "parameters".
Would this mean query string parameters, POST variables, key-value pair headers, or something else?
I guess I'm just confused by what is meant by the word "parameters" in the context of all these different HTTP request methods. In other words, how would I pass the API key as a "parameter" to their API when I could be using GET, POST, PUT or DELETE? My understanding was that only HTTP GET can handle query string params, and that HTTP POST can only handle POST variables. And I have never used PUT or DELETE before so I'm not sure what they require.
So I ask: what mechanism can I use to send the API key/signature via all 4 types of request methods, or do they all support the processing of query string parameters? Thanks in advance.

You can try this. It works for my HttpClient application with POST request.
DefaultHttpClient httpClient = new DefaultHttpClient();
httpClient.getParams().setParameter(name, value);
......
For Example, I set the connection timeout:
httpClient.getParams().setIntParameter(HttpConnectionParams.CONNECTION_TIMEOUT, httpTimeout);
Then later, to send(execute) the request:
HttpResponse response = httpClient.execute([My HttpPost instance was here, but I think you can use HttpGet, HttpPut, and HttpDelete here as well]);

All verbs can use request parameters (also known as query parameters) and they will be available to the server in the same way regardless of if you also send a body.
In your example (Gengo) there is a good example on there page about authentication.