My team is building a basic HTTP server from scratch in Java, but our reader threads block once they run out of request text to read from the socket's input stream. A number of points unique to our situation that don't match up with questions asked previously:
The basic code:
public void readSocket() {
receivedTime = System.currentTimeMillis();
requestFile = new File("recovery/" + receivedTime + ".txt");
try(
FileWriter fw = new FileWriter(requestFile);
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
BufferedWriter out = new BufferedWriter(fw);
)
{
String line;
while((line = in.readLine()) != null){ //TODO: this is where it blocks after reading past the last line of the request.
out.write(line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
readLine() returns null only if "the end of the stream has been reached", ie the socket has been closed by the other party. When readLine() reads a line break with no preceding data, it returns a non-null String that has a length of 0. So you need to fix you while loop accordingly:
public void readSocket() {
receivedTime = System.currentTimeMillis();
requestFile = new File("recovery/" + receivedTime + ".txt");
try(
FileWriter fw = new FileWriter(requestFile);
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
BufferedWriter out = new BufferedWriter(fw);
)
{
String line;
// read request headers...
do {
line = in.readLine();
if (line == null) return; // socket closed
out.write(line);
out.NewLine();
out.flush();
if (line.isEmpty()) break; // end of headers reached
// process line as needed...
}
while (true);
// check received headers for presence of a message
// body, and read it if needed. Refer to RFC 2616
// Section 4.4 for details...
// process request as needed...
} catch (IOException e) {
e.printStackTrace();
}
}
Also see:
While reading from socket how to detect when the client is done sending the request?