Various extensions to the HTTP API

- A response is returned on the event of a HTTP error (such as 404).
 - Responses include the response headers.

src/main/java/dan200/computercraft/core/apis/HTTPAPI.java

@@ -52,12 +52,16 @@ public class HTTPAPI implements ILuaAPI
                     if( h.wasSuccessful() ) {
                         // Queue the "http_success" event
                         final BufferedReader contents = h.getContents();
-                        final int responseCode = h.getResponseCode();
-                        final Object result = wrapBufferedReader( contents, responseCode );
+                        final Object result = wrapBufferedReader( contents, h.getResponseCode(), h.getResponseHeaders() );
                         m_apiEnvironment.queueEvent( "http_success", new Object[] { url, result } );
                     } else {
                         // Queue the "http_failure" event
-                        m_apiEnvironment.queueEvent( "http_failure", new Object[] { url, "Could not connect" } );
+                        BufferedReader contents = h.getContents();
+                        Object result = null;
+                        if( contents != null ) {
+                            result = wrapBufferedReader( contents, h.getResponseCode(), h.getResponseHeaders() );
+                        }
+                        m_apiEnvironment.queueEvent( "http_failure", new Object[]{ url, "Could not connect", result } );
                     }
                     it.remove();
                 }
@@ -65,7 +69,7 @@ public class HTTPAPI implements ILuaAPI
         }
     }
     
-    private static ILuaObject wrapBufferedReader( final BufferedReader reader, final int responseCode )
+    private static ILuaObject wrapBufferedReader( final BufferedReader reader, final int responseCode, final Map<String, Map<Integer, String>> responseHeaders )
     {
         return new ILuaObject() {
             @Override
@@ -75,7 +79,8 @@ public class HTTPAPI implements ILuaAPI
                     "readLine",
                     "readAll",
                     "close",
-                    "getResponseCode"
+                    "getResponseCode",
+                    "getResponseHeaders",
                 };
             }
             
@@ -131,6 +136,11 @@ public class HTTPAPI implements ILuaAPI
                         // getResponseCode
                         return new Object[] { responseCode };
                     }
+                    case 4:
+                    {
+                        // getResponseHeaders
+                        return new Object[] { responseHeaders };
+                    }
                     default:
                     {
                         return null;

src/main/java/dan200/computercraft/core/apis/HTTPRequest.java

@@ -12,6 +12,8 @@ import java.io.*;
 import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.regex.Pattern;
 
@@ -130,7 +132,16 @@ public class HTTPRequest
                     }
 
                     // Read response
-                    InputStream is = connection.getInputStream();
+                    InputStream is;
+                    int code = connection.getResponseCode();
+                    boolean responseSuccess;
+                    if (code >= 200 && code < 400) {
+                        is = connection.getInputStream();
+                        responseSuccess = true;
+                    } else {
+                        is = connection.getErrorStream();
+                        responseSuccess = false;
+                    }
                     InputStreamReader isr;
                     try
                     {
@@ -192,9 +203,21 @@ public class HTTPRequest
                         {
                             // We completed
                             m_complete = true;
-                            m_success = true;
+                            m_success = responseSuccess;
                             m_result = result.toString();
                             m_responseCode = connection.getResponseCode();
+
+                            Map<String, Map<Integer, String>> headers = m_responseHeaders = new HashMap<String, Map<Integer, String>>();
+                            for (Map.Entry<String, List<String>> header : connection.getHeaderFields().entrySet()) {
+                                Map<Integer, String> values = new HashMap<Integer, String>();
+
+                                int i = 0;
+                                for (String value : header.getValue()) {
+                                    values.put(++i, value);
+                                }
+
+                                headers.put(header.getKey(), values);
+                            }
                         }
                     }
 
@@ -241,6 +264,12 @@ public class HTTPRequest
         }
     }
 
+    public Map<String, Map<Integer, String>> getResponseHeaders() {
+        synchronized (m_lock) {
+            return m_responseHeaders;
+        }
+    }
+
     public boolean wasSuccessful()
     {
         synchronized(m_lock) {
@@ -270,4 +299,5 @@ public class HTTPRequest
     private boolean m_success;
     private String m_result;
     private int m_responseCode;
+    private Map<String, Map<Integer, String>> m_responseHeaders;
 }

src/main/resources/assets/computercraft/lua/bios.lua

@@ -643,11 +643,11 @@ if http then
         local ok, err = nativeHTTPRequest( _url, _post, _headers )
         if ok then
             while true do
-                local event, param1, param2 = os.pullEvent()
+                local event, param1, param2, param3 = os.pullEvent()
                 if event == "http_success" and param1 == _url then
                     return param2
                 elseif event == "http_failure" and param1 == _url then
-                    return nil, param2
+                    return nil, param2, param3
                 end
             end
         end