Add GitHub client class for new API

Change-Id: I8f4681353bcfcffc7efbc9bb4f726dc61a45a563
Signed-off-by: Kevin Sawicki <kevin@github.com>
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>

3 files changed, 244 insertions, 0 deletions

diff --git a/org.eclipse.mylyn.github.core/META-INF/MANIFEST.MF b/org.eclipse.mylyn.github.core/META-INF/MANIFEST.MF
index bb48a03a..2494f24a 100644
--- a/org.eclipse.mylyn.github.core/META-INF/MANIFEST.MF
+++ b/org.eclipse.mylyn.github.core/META-INF/MANIFEST.MF
@@ -10,4 +10,5 @@ Require-Bundle: org.eclipse.core.runtime;bundle-version="3.5.0",
  org.eclipse.mylyn.tasks.core;bundle-version="3.2.0",
  org.eclipse.mylyn.commons.net;bundle-version="3.2.0"
 Import-Package: com.google.gson;version="1.6.0",
+ com.google.gson.reflect;version="1.6.0",
  org.apache.commons.logging
diff --git a/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/GitHubClient.java b/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/GitHubClient.java
new file mode 100644
index 00000000..765e90be
--- /dev/null
+++ b/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/GitHubClient.java
@@ -0,0 +1,238 @@
+/*******************************************************************************
+ *  Copyright (c) 2011 GitHub Inc.
+ *  All rights reserved. This program and the accompanying materials
+ *  are made available under the terms of the Eclipse Public License v1.0
+ *  which accompanies this distribution, and is available at
+ *  http://www.eclipse.org/legal/epl-v10.html
+ *
+ *  Contributors:
+ *    Kevin Sawicki (GitHub Inc.) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.mylyn.github.internal;
+
+import com.google.gson.FieldNamingPolicy;
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonParseException;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.lang.reflect.Type;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import org.apache.commons.httpclient.Credentials;
+import org.apache.commons.httpclient.HostConfiguration;
+import org.apache.commons.httpclient.HttpClient;
+import org.apache.commons.httpclient.HttpMethod;
+import org.apache.commons.httpclient.HttpMethodBase;
+import org.apache.commons.httpclient.NameValuePair;
+import org.apache.commons.httpclient.UsernamePasswordCredentials;
+import org.apache.commons.httpclient.auth.AuthScope;
+import org.apache.commons.httpclient.auth.BasicScheme;
+import org.apache.commons.httpclient.methods.GetMethod;
+import org.apache.commons.httpclient.methods.PostMethod;
+import org.apache.commons.httpclient.protocol.Protocol;
+
+/**
+ * Client class for interacting with GitHub HTTP/JSON API.
+ *
+ * @author Kevin Sawicki (kevin@github.com)
+ */
+public class GitHubClient {
+
+	private static final AuthScope ANY_SCOPE = new AuthScope(
+			AuthScope.ANY_HOST, AuthScope.ANY_PORT);
+
+	private HostConfiguration hostConfig;
+
+	private HttpClient client = new HttpClient();
+
+	private Gson gson = new GsonBuilder()
+			.setDateFormat(IGitHubConstants.DATE_FORMAT)
+			.setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
+			.create();
+
+	private boolean sendCredentials = false;
+
+	/**
+	 * Create default client
+	 */
+	public GitHubClient() {
+		this.hostConfig = new HostConfiguration();
+		this.hostConfig.setHost(IGitHubConstants.HOST_API, -1,
+				Protocol.getProtocol(IGitHubConstants.PROTOCOL_HTTPS));
+	}
+
+	/**
+	 * Create client for configuration
+	 *
+	 * @param configuration
+	 */
+	public GitHubClient(HostConfiguration configuration) {
+		this.hostConfig = configuration;
+	}
+
+	/**
+	 * Create standard post method
+	 *
+	 * @param uri
+	 * @return post
+	 */
+	protected PostMethod createPost(String uri) {
+		PostMethod method = new PostMethod(uri);
+		setMethodDefaults(method);
+		return method;
+	}
+
+	/**
+	 * Set method defaults
+	 *
+	 * @param method
+	 * @return method
+	 */
+	protected HttpMethod setMethodDefaults(HttpMethod method) {
+		if (this.sendCredentials) {
+			method.setDoAuthentication(true);
+			method.getHostAuthState().setPreemptive();
+			method.getHostAuthState().setAuthScheme(new BasicScheme());
+		}
+		return method;
+	}
+
+	/**
+	 * Create get method
+	 *
+	 * @param uri
+	 * @return get method
+	 */
+	protected GetMethod createGet(String uri) {
+		GetMethod method = new GetMethod(uri);
+		method.setFollowRedirects(true);
+		setMethodDefaults(method);
+		return method;
+	}
+
+	/**
+	 * Set credentials
+	 *
+	 * @param user
+	 * @param password
+	 */
+	public void setCredentials(String user, String password) {
+		this.sendCredentials = user != null && password != null;
+		Credentials credentials = null;
+		if (this.sendCredentials)
+			credentials = new UsernamePasswordCredentials(user, password);
+		this.client.getState().setCredentials(ANY_SCOPE, credentials);
+	}
+
+	/**
+	 * Parse json to specified type
+	 *
+	 * @param <V>
+	 * @param method
+	 * @param type
+	 * @return type
+	 * @throws IOException
+	 */
+	protected <V> V parseJson(HttpMethodBase method, Type type)
+			throws IOException {
+		InputStream stream = method.getResponseBodyAsStream();
+		if (stream == null)
+			throw new JsonParseException("Empty body"); //$NON-NLS-1$
+		InputStreamReader reader = new InputStreamReader(stream);
+		return this.gson.fromJson(reader, type);
+	}
+
+	/**
+	 * Get name value pairs for data map.
+	 *
+	 * @param data
+	 * @return name value pair array
+	 */
+	protected NameValuePair[] getPairs(Map<String, String> data) {
+		NameValuePair[] pairs = new NameValuePair[data.size()];
+		int i = 0;
+		for (Entry<String, String> entry : data.entrySet()) {
+			pairs[i] = new NameValuePair(entry.getKey(), entry.getValue());
+			i++;
+		}
+		return pairs;
+	}
+
+	/**
+	 * Get response from uri and bind to specified type
+	 *
+	 * @param <V>
+	 * @param uri
+	 * @param params
+	 * @param type
+	 * @return V
+	 * @throws IOException
+	 */
+	public <V> V get(String uri, Map<String, String> params, Type type)
+			throws IOException {
+		GetMethod method = createGet(uri);
+		if (params != null && !params.isEmpty())
+			method.setQueryString(getPairs(params));
+
+		try {
+			int status = this.client.executeMethod(this.hostConfig, method);
+			switch (status) {
+			case 200:
+				return parseJson(method, type);
+			case 404:
+			case 500:
+				RequestError error = parseJson(method, RequestError.class);
+				throw new RequestException(error);
+			default:
+				throw new IOException(method.getStatusText());
+			}
+		} catch (JsonParseException jpe) {
+			throw new IOException(jpe);
+		} finally {
+			method.releaseConnection();
+		}
+	}
+
+	/**
+	 * Post data to uri
+	 *
+	 * @param <V>
+	 * @param uri
+	 * @param params
+	 * @param type
+	 * @return response
+	 * @throws IOException
+	 */
+	public <V> V post(String uri, Map<String, String> params, Type type)
+			throws IOException {
+		PostMethod method = createPost(uri);
+		if (params != null && !params.isEmpty())
+			for (Entry<String, String> entry : params.entrySet())
+				method.addParameter(entry.getKey(), entry.getValue());
+
+		try {
+			int status = this.client.executeMethod(this.hostConfig, method);
+			switch (status) {
+			case 200:
+			case 201:
+				if (type != null)
+					return parseJson(method, type);
+				break;
+			case 404:
+			case 500:
+				RequestError error = parseJson(method, RequestError.class);
+				throw new RequestException(error);
+			default:
+				throw new IOException(method.getStatusText());
+			}
+		} finally {
+			method.releaseConnection();
+		}
+		return null;
+	}
+
+}
diff --git a/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/IGitHubConstants.java b/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/IGitHubConstants.java
index 290d616e..424e26d2 100644
--- a/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/IGitHubConstants.java
+++ b/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/IGitHubConstants.java
@@ -42,4 +42,9 @@ public interface IGitHubConstants {
 	 */
 	String PROTOCOL_HTTPS = "https"; //$NON-NLS-1$
 
+	/**
+	 * DATE_FORMAT
+	 */
+	String DATE_FORMAT = "yyyy-MM-dd'T'HH:mm:ss'Z'"; //$NON-NLS-1$
+
 }