com.github.alexdlaird.http.DefaultHttpClient Maven / Gradle / Ivy
/*
* Copyright (c) 2023 Alex Laird
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.github.alexdlaird.http;
import com.github.alexdlaird.util.StringUtils;
import com.google.gson.FieldNamingPolicy;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonSyntaxException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.charset.Charset;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import static com.github.alexdlaird.util.StringUtils.isNotBlank;
/**
* A default client for executing JSON-based HTTP requests.
*
* Basic Usage
*
* final HttpClient httpClient = new DefaultHttpClient.Builder();
*
* final SomePOJORequest postPojo = new MyPOJO("id", "data");
* final Response<SomePOJOResponse> postResponse = httpClient.post("http://localhost/pojo",
* postPojo,
* SomePOJOResponse.class);
*
* final Response<SomePOJOResponse> getResponse = httpClient.get("http://localhost/pojo/id",
* SomePOJOResponse.class);
*
* final SomePOJORequest putPojo = new MyPOJO("updated-data");
* final Response<SomePOJOResponse> postResponse = httpClient.post("http://localhost/pojo/id",
* putPojo,
* SomePOJOResponse.class);
*
* final Response<Map> deleteResponse = httpClient.delete("http://localhost/pojo/id");
*
*/
public class DefaultHttpClient implements HttpClient {
private static final Logger LOGGER = Logger.getLogger(String.valueOf(DefaultHttpClient.class));
private final Gson gson;
private final String encoding;
private final String contentType;
private final int timeout;
private DefaultHttpClient(final Builder builder) {
this.encoding = builder.encoding;
this.contentType = builder.contentType;
this.timeout = builder.timeout;
this.gson = new GsonBuilder()
.setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
.create();
}
@Override
public Response get(final String url,
final List parameters,
final Map additionalHeaders,
final Class clazz) {
try {
return execute(urlWithParameters(url, parameters), null, "GET",
additionalHeaders, clazz);
} catch (IOException e) {
throw new HttpClientException("HTTP GET error", e);
}
}
@Override
public Response post(final String url,
final R request,
final List parameters,
final Map additionalHeaders,
final Class clazz) {
try {
return execute(urlWithParameters(url, parameters), convertRequestToString(request), "POST",
additionalHeaders, clazz);
} catch (IOException e) {
throw new HttpClientException("HTTP POST error", e);
}
}
@Override
public Response put(final String url,
final R request,
final List parameters,
final Map additionalHeaders,
final Class clazz) {
try {
return execute(urlWithParameters(url, parameters), convertRequestToString(request), "PUT",
additionalHeaders, clazz);
} catch (IOException e) {
throw new HttpClientException("HTTP PUT error", e);
}
}
@Override
public Response delete(final String url,
final List parameters,
final Map additionalHeaders,
final Class clazz) {
try {
return execute(urlWithParameters(url, parameters), null, "DELETE",
additionalHeaders, clazz);
} catch (IOException e) {
throw new HttpClientException("HTTP DELETE error", e);
}
}
private void appendDefaultsToConnection(final HttpURLConnection httpUrlConnection,
final Map additionalHeaders) {
httpUrlConnection.setRequestProperty("Content-Type", contentType);
if (additionalHeaders != null) {
for (final Map.Entry entry : additionalHeaders.entrySet()) {
httpUrlConnection.setRequestProperty(entry.getKey(), entry.getValue());
}
}
}
/**
* Override this method if you could like to implement a custom URL connection.
*
* @param url The URL to connect to.
* @return A URL connection.
* @throws IOException An I/O exception has occurred.
*/
protected HttpURLConnection createHttpUrlConnection(final String url) throws IOException {
return (HttpURLConnection) new URL(url).openConnection();
}
private String convertRequestToString(final T request) {
if (request != null) {
return gson.toJson(request);
} else {
return null;
}
}
private T convertResponseFromString(final String response, final Class clazz) {
if (isNotBlank(response)) {
try {
return gson.fromJson(response, clazz);
} catch (JsonSyntaxException ex) {
return null;
}
} else {
return null;
}
}
private String urlWithParameters(final String url,
final List parameters)
throws UnsupportedEncodingException {
final StringBuilder stringBuilder = new StringBuilder();
stringBuilder.append(url);
if (parameters != null && parameters.size() > 0) {
boolean first = true;
for (final Parameter parameter : parameters) {
if (!first) {
stringBuilder.append("&");
} else {
stringBuilder.append("?");
first = false;
}
stringBuilder.append(URLEncoder.encode(parameter.getName(), encoding));
stringBuilder.append("=");
stringBuilder.append(URLEncoder.encode(parameter.getValue(), encoding));
}
}
return stringBuilder.toString();
}
private Response execute(final String url,
final String body,
final String method,
final Map additionalHeaders,
final Class clazz) throws IOException {
HttpURLConnection httpUrlConnection = null;
OutputStream outputStream = null;
InputStream inputStream = null;
try {
httpUrlConnection = createHttpUrlConnection(url);
httpUrlConnection.setRequestMethod(method);
httpUrlConnection.setConnectTimeout(timeout);
httpUrlConnection.setReadTimeout(timeout);
appendDefaultsToConnection(httpUrlConnection, additionalHeaders);
modifyConnection(httpUrlConnection);
if (isNotBlank(body)) {
httpUrlConnection.setDoOutput(true);
httpUrlConnection.connect();
outputStream = httpUrlConnection.getOutputStream();
outputStream.write(body.getBytes(Charset.forName(encoding)));
} else {
httpUrlConnection.setRequestProperty("Content-Length", "0");
httpUrlConnection.connect();
}
inputStream = httpUrlConnection.getInputStream();
final String responseBody = StringUtils.streamToString(inputStream, Charset.forName(encoding));
return new Response<>(httpUrlConnection.getResponseCode(),
convertResponseFromString(responseBody, clazz),
responseBody,
httpUrlConnection.getHeaderFields());
} catch (Exception ex) {
String msg = "An unknown error occurred when performing the operation";
int statusCode = -1;
String errorResponse = null;
if (httpUrlConnection != null) {
try {
statusCode = httpUrlConnection.getResponseCode();
errorResponse = StringUtils.streamToString(httpUrlConnection.getErrorStream(), Charset.forName(encoding));
msg = "An error occurred when performing the operation (" + httpUrlConnection.getResponseCode() + "): " + errorResponse;
} catch (IOException | NullPointerException ignored) {
}
}
throw new HttpClientException(msg, ex, url, statusCode, errorResponse);
} finally {
if (httpUrlConnection != null) {
httpUrlConnection.disconnect();
}
try {
if (outputStream != null) {
outputStream.close();
}
if (inputStream != null) {
inputStream.close();
}
} catch (IOException ex) {
LOGGER.log(Level.INFO, "Unable to close connection", ex);
}
}
}
/**
* Builder for a {@link DefaultHttpClient}, see docs for that class for example usage.
*/
public static class Builder {
private String encoding = "UTF-8";
private String contentType = "application/json";
public int timeout = 4000;
/**
* Default encoding for requests.
*/
public Builder withEncoding(final String encoding) {
this.encoding = encoding;
return this;
}
/**
* Default contentType header for requests.
*/
public Builder withContentType(final String contentType) {
this.contentType = contentType;
return this;
}
/**
* Default timeout for requests.
*/
public Builder withTimeout(final int timeout) {
this.timeout = timeout;
return this;
}
public DefaultHttpClient build() {
return new DefaultHttpClient(this);
}
}
}
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