Connection and connection request timeout

Question

I am using Http Apache Components to perform the http interactions. I need to adjust my http client. For this purpose I have two parameters: connection timeout and connection request timeout. In library documentation and in source code(no comments were found) I didn't found definition of this terms. I need to know what do they exactly mean. May be they were defined in HTTP protocol documentation but I can't find it. So, my question is what do this two terms mean and how they distinct from each other.

Solution 1

HttpClient has a way to set connection and socket timeout (setConnectionTimeout() and setTimeout()) according to the HttpClient javadocs.

Connection timeout is the timeout until a connection with the server is established.

Socket timeout is the timeout to receive data (socket timeout).

Example:

Let's say you point your browser to access a web page. If the server does not anwser in X seconds, a connection timeout will occur. But if it establishes the connection, then the server will start to process the result for the browser. If it does not ends this processing in Y seconds, a socket timeout will occur.

Solution 2

From the documentation:

/**
 * Returns the timeout in milliseconds used when requesting a connection
 * from the connection manager. A timeout value of zero is interpreted
 * as an infinite timeout.
 * <p>
 * A timeout value of zero is interpreted as an infinite timeout.
 * A negative value is interpreted as undefined (system default).
 * </p>
 * <p>
 * Default: {@code -1}
 * </p>
 */
public int getConnectionRequestTimeout() {
    return connectionRequestTimeout;
}

/**
 * Determines the timeout in milliseconds until a connection is established.
 * A timeout value of zero is interpreted as an infinite timeout.
 * <p>
 * A timeout value of zero is interpreted as an infinite timeout.
 * A negative value is interpreted as undefined (system default).
 * </p>
 * <p>
 * Default: {@code -1}
 * </p>
 */
public int getConnectTimeout() {
    return connectTimeout;
}

This is how the code should look:

HttpClientBuilder clientBuilder = HttpClientBuilder.create();
RequestConfig.Builder requestBuilder = RequestConfig.custom();
// Connection Timeout to establish a connection
requestBuilder = requestBuilder.setConnectTimeout(connectTimeoutMillis);
// Timeout to get a connection from the connection manager for the Http Client
requestBuilder = requestBuilder.setConnectionRequestTimeout(requestTimeoutMillis);
// Timeout between two data packets from the server
requestBuilder = requestBuilder.setSocketTimeout(requestTimeoutMillis);
clientBuilder.setDefaultRequestConfig(requestBuilder.build());
CloseableHttpClient httpClient = clientBuilder.build();