Develop Reference

How to set Headers if I am using responde.sendRedirect

Previous scenario:-
User logins through Portal and user clicks on some link, the portal sends the request which contains Headers(user name) to reporting server to retrieve report .
Current Scenario:-
The portal was re-written and Headers are now being in JSON format, the Header values through which the authentication was being done is named in a different way. We thought to intercept the request and rearrange the Headers in a way how the reporting server reads so that request can go through.
We thought of deploying this new Interceptor application in a new Tomcat server on the same box where Reporting server is , and I cannot use RequestDispatcher.forward , and sendRedirect if I use nullifies any Header values which I add before doing sendRedirect as browser will issue a new request.
I tried using HttpClient , to open a new Http connection to reporting server with adding Header values , but when I check the same in Fiddler or HTTP Header spy in my chrome browser I cannot see any Header values in the client request object. And I am trying to capture the response object from reporting server and set the same in my original request , and set that in the original response object in my servlet to push to client browser. But as my Header values are not getting set in HTTPClient Post request the request is never fulfilled.
Below is the same code for creating HTTPClient from my interceptor servlet.
String url = "someurl";
HttpClient client = HttpClientBuilder.create().build();
//HttpGet get = new HttpGet();
HttpPost post = new HttpPost(url);
try {
String smUser = "<user name>";
String grps = "<some values>";
post.addHeader(<headerKey1>,<smUser>);
post.addHeader(<headerkey2>, grps);
HttpResponse response = client.execute(post);
BufferedReader buff = new BufferedReader(new InputStreamReader(
response.getEntity().getContent()));
response.getEntity().getContent();
String inputLine;
StringBuffer html = new StringBuffer();
while ((inputLine = buff.readLine()) != null) {
html.append(inputLine);
}
buff.close();
System.out.println("URL Content... \n" + html.toString());
I know I can use url rewritting , but that is not an option , let me know if there is any other way through which my interceptor can change the Header values and pass the request to reporting server , so that user can access reports.

I alse was blockd by this issue. Code like below, but the header I added hasn't been sent to target service. By the way, there're two different services
response.setHeader(key, value)
response.sendRedirect(target_url)

While trying to send POST request in HTTPCLIENT -JAVA, getting 400 Bad Request

I am trying to POST a request using JAVA HTTPCLIENT, and while doing so, I am getting 404 Bad Request.
I tried writing the JAVA code in Eclipse and got 404 Bad Request and tried sending the request through POSTMAN and received HTTP Status 500
package com.apex.customer.service;
public class CustServicePostTest {
public static void main(String[] args) throws ClientProtocolException, IOException {
String url = "http://www.thomas-bayer.com/sqlrest/CUSTOMER/102";
//create the http client
HttpClient client = HttpClientBuilder.create().build();
//create the post message
HttpPost post = new HttpPost(url);
List<NameValuePair> urlParameters = new ArrayList<NameValuePair>();
urlParameters.add(new BasicNameValuePair("ID", "102"));
urlParameters.add(new BasicNameValuePair("FIRSTNAME", "Apex"));
urlParameters.add(new BasicNameValuePair("LASTNAME", "Consultancy"));
urlParameters.add(new BasicNameValuePair("STREET", "Shell Blvd"));
urlParameters.add(new BasicNameValuePair("CITY", "Fremont"));
post.setEntity(new UrlEncodedFormEntity(urlParameters));
HttpResponse response = client.execute(post);
System.out.println(response.getStatusLine().getStatusCode());
System.out.println("Parameters : " + urlParameters);
System.out.println("Response Code: " + response);
System.out.println(response.getStatusLine().getReasonPhrase());
}
}
I am looking for 200 OK request.

The issue here is due few mistakes:
First is related to the input format. The code you're using tries to map key and values, but as I could see from this guide, it expects a XML format in a plain text as input.
The second mistake is that you are trying to post over an existing ID. In this case, to create a resource you should use http://www.thomas-bayer.com/sqlrest/CUSTOMER/
So in this case in order to make it work, try something like this:
String url = "http://www.thomas-bayer.com/sqlrest/CUSTOMER/";
HttpClient client = HttpClientBuilder.create().build();
HttpPost post = new HttpPost(url);
String xml = "<resource>";
xml += "<ID>102</ID>";
xml += "<FIRSTNAME>Apex</FIRSTNAME>";
xml += "<LASTNAME>Consultancy</LASTNAME>";
xml += "<STREET>Shell Blvd</STREET>";
xml += "<CITY>Fremont</CITY>";
xml += "</resource>";
post.setEntity(new StringEntity(xml));
HttpResponse response = client.execute(post);
System.out.println(response.getStatusLine().getStatusCode());
System.out.println("Response Code: " + response);
System.out.println(response.getStatusLine().getReasonPhrase());
It is also very useful to learn another way to test it with tools like curl command line utility. For example you can POST a product like this:
curl -X POST http://www.thomas-bayer.com/sqlrest/PRODUCT/ -d '<resource><ID>103</ID><NAME>X</NAME><PRICE>2.2</PRICE></resource>'
Once you solve this, it will be important to get used with HTTP codes. For example a 500 error means something wrong on the server side while a 404 usually means that you're hitting an invalid endpoint (it does not exists).
Finally, I'll not discuss why are you using this project to send HTTP requests to a server - but keep in mind that this is not a very common way to go. Currently the REST with JSON would be much more interesting and enjoyable :) In case you're interested on it, take a look on Spring Boot REST

POST request to server using java URLConnnection with params and file inputs

POST request to server using java URLConnnection
I need to send a POST request with the two parameters below:
param1=value1
param2=value2
And also I need to send a file.
In the case of Apache these 2 two(sending params and file) things are handled like below
post.setQueryString(queryString) // queryString is url encoded for eg: param1=value1&param2=value2
post.setRequestEntity(entity) // entity is constructed using file input stream with corresponding format
Please let me know if you have anything related to this problem.
Please note: When I try using Google Chrome REST client plug-in, I am getting the response as below (tried with all request content-types)
UNSUPPORTED FILE FORMAT: 'multipart/form-data' is not a supported content-type
Response code is 400.

Try this API from Apache to send request internally with POST method.
The below is the sample Code to use API
List<org.apache.http.NameValuePair> list =new ArrayList<org.apache.http.NameValuePair>();
HttpPost postMethod = new HttpPost("http://yoururl/ProjectName");
list.add(new BasicNameValuePair("param1", "param1 Value")) ;
postMethod.setEntity(new UrlEncodedFormEntity(list));
HttpClient client = HttpClientBuilder.create().build();
HttpResponse response = client.execute(postMethod);
InputStream is = response.getEntity().getContent();

HTTP Bad Request response to Java POST call

I'm attempting to query a REST api using POST requests in a java application. I think I've set everything correctly, but I keep getting a Bad Request response.
HttpPost request = new HttpPost(requestURI);
request.addHeader("accept", "application/json");
request.addHeader(HttpHeaders.CONTENT_TYPE, "application/json");
HttpEntity entity = new StringEntity(requestBody + new Integer(PatientId).toString() + "}");
request.setEntity(entity);
The requestBody, accompanied by the number and curly brace, are valid JSON, and the requestURI is copy and pasted straight out of the API documentation, so I know I shouldn't be getting a Bad Request due to those.
Am I missing something in the setup?

The Content-Length header is missing. Some servers don't report the correct 4xx error (411 Length Required) and just issue a generic Bad Request error.

It ended up being a random slash that wasn't included in my URI.

How to pass data in HTTP Header while redirecting a request in Java

is it possible to pass some data in HTTP Header, while redirecting a request from one server to another.
Here is my scenario,
I have one generic filter, via which every request is passing.
Now, based on some condition, I'm redirecting the request to some different server using the API objHttpServletResponse.sendRedirect(strURL).
But, the issue is, when I'm setting some data in response header like objHttpServletResponse.setHeader("Key", "Value"); That's not available in the redirected server.
So, my questions are,
1. Is there any way to pass some data in header while redirecting a request?
2. If not, what are the other possible ways to send some data while redirecting a request?
Please Note: few other ways, like
using URL parameters:
objHttpServletResponse.sendRedirect(strURL+"?param="+ strParamValue);
or
using session:
HttpSession session = httpRequest.getSession();
session.setAttribute("Key", "Value");
is not what I'm expecting.

The headers you set are written to the response that gets sent to the client, along with a Location header and a status code. See Redirecting a request using servlets and the "setHeader" method not working
The client is then supposed to send an identical request to the URL you specified in the Location header. Identical to the request it sent to you.
You want the browser to send a header you specify along with the redirected request. Have you considered adding a (domain) Cookie header? Some googling leads me to believe that cookies set in a redirect response will get picked up by most browsers. See http://blog.dubbelboer.com/2012/11/25/302-cookie.html

Please have a look at Apache HttpClient.
This example adds several parameters to the post request :
String url = "https://selfsolve.apple.com/wcResults.do";
HttpClient client = HttpClientBuilder.create().build();
HttpPost post = new HttpPost(url);
// add header
post.setHeader("User-Agent", USER_AGENT);
List<NameValuePair> urlParameters = new ArrayList<NameValuePair>();
urlParameters.add(new BasicNameValuePair("sn", "C02G8416DRJM"));
urlParameters.add(new BasicNameValuePair("cn", ""));
urlParameters.add(new BasicNameValuePair("locale", ""));
urlParameters.add(new BasicNameValuePair("caller", ""));
urlParameters.add(new BasicNameValuePair("num", "12345"));
post.setEntity(new UrlEncodedFormEntity(urlParameters));
HttpResponse response = client.execute(post);
System.out.println("Response Code : "
+ response.getStatusLine().getStatusCode());

The problem is that the redirect() method of the response initiates a new request altogether, thereby loosing the attributes that were set before redirecting. Luckily there is a fluent way of solving the problem still.
response.setHeader("Key", "Value");
request.getRequestDispatcher("redirecturl").forward(request, response);
Then in your destination you can do
response.getHeaders("key")

You can use JS redirect, i.e. instead of calling sendRedirect return HTML page with embedded javascript that will do redirect setting headers you need.
However, using GET parameters is really the best solution. If you have concerns about users altering parameters manually - use MAC code to protect parameters.See
Message authentication code
In simplest form, ?p1=1&p2=2&mac={mac value}, where {mac value} = md5('MY_SECRET_KEY' + 'p1=1&p2=2').
Receiving side can recalculate MAC and compare it with provided one. Since external users can not know 'MY_SECRET_KEY', they will not be able to make valid MAC.

Have you checked the HTTP request/response from/to server? You can use a number of plugins on chrome or firefox to check that. You would be able to see if value is being passed from your server to another server or not
Also retrieve the header using httpResponse.getHeader("Key"); not using request.getHeader("key"). One of my colleague was facing same issue some days back, he was using request to fetch header values