ObjFW  Documentation

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017,
 *               2018
 *   Jonathan Schleifer <js@heap.zone>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#define OF_HTTPCLIENT_M

#include "config.h"

#include <errno.h>
#include <string.h>

#import "OFHTTPClient.h"
#import "OFData.h"
#import "OFDictionary.h"
#import "OFHTTPRequest.h"
#import "OFHTTPResponse.h"
#import "OFKernelEventObserver.h"
#import "OFNumber.h"
#import "OFRunLoop.h"
#import "OFString.h"
#import "OFTCPSocket.h"
#import "OFURL.h"

#import "OFAlreadyConnectedException.h"
#import "OFHTTPRequestFailedException.h"
#import "OFInvalidArgumentException.h"
#import "OFInvalidEncodingException.h"
#import "OFInvalidFormatException.h"
#import "OFInvalidServerReplyException.h"
#import "OFNotImplementedException.h"
#import "OFNotOpenException.h"
#import "OFOutOfMemoryException.h"
#import "OFOutOfRangeException.h"
#import "OFTruncatedDataException.h"
#import "OFUnsupportedProtocolException.h"
#import "OFUnsupportedVersionException.h"
#import "OFWriteFailedException.h"

#define REDIRECTS_DEFAULT 10

@interface OFHTTPClientRequestHandler: OFObject
{
@public
	OFHTTPClient *_client;
	OFHTTPRequest *_request;
	unsigned int _redirects;
	id _context;
	bool _firstLine;
	OFString *_version;
	int _status;
	OFMutableDictionary OF_GENERIC(OFString *, OFString *) *_serverHeaders;
}

- (instancetype)initWithClient: (OFHTTPClient *)client
		       request: (OFHTTPRequest *)request
		     redirects: (unsigned int)redirects
		       context: (id)context;
- (void)start;
- (void)closeAndReconnect;
@end

@interface OFHTTPClientRequestBodyStream: OFStream <OFReadyForWritingObserving>
{
	OFHTTPClientRequestHandler *_handler;
	OFTCPSocket *_socket;
	uintmax_t _toWrite;
	bool _atEndOfStream;
}

- (instancetype)initWithHandler: (OFHTTPClientRequestHandler *)handler
			 socket: (OFTCPSocket *)sock;
@end

@interface OFHTTPClientResponse: OFHTTPResponse <OFReadyForReadingObserving>
{
	OFTCPSocket *_socket;
	bool _hasContentLength, _chunked, _keepAlive, _atEndOfStream;
	uintmax_t _toRead;
}

@property (nonatomic, setter=of_setKeepAlive:) bool of_keepAlive;

- (instancetype)initWithSocket: (OFTCPSocket *)sock;
@end

@interface OFHTTPClient_SyncPerformer: OFObject <OFHTTPClientDelegate>
{
	OFHTTPClient *_client;
	OFObject <OFHTTPClientDelegate> *_delegate;
	OFHTTPResponse *_response;
}

- (instancetype)initWithClient: (OFHTTPClient *)client;
- (OFHTTPResponse *)performRequest: (OFHTTPRequest *)request
			 redirects: (unsigned int)redirects
			   context: (id)context;
@end

static OFString *
constructRequestString(OFHTTPRequest *request)
{
	void *pool = objc_autoreleasePoolPush();
	of_http_request_method_t method = [request method];
	OFURL *URL = [request URL];
	OFString *path;
	OFString *user = [URL user], *password = [URL password];
	OFMutableString *requestString;
	OFMutableDictionary OF_GENERIC(OFString *, OFString *) *headers;
	OFEnumerator OF_GENERIC(OFString *) *keyEnumerator, *objectEnumerator;
	OFString *key, *object;

	if ([URL path] != nil)
		path = [URL URLEncodedPath];
	else
		path = @"/";

	requestString = [OFMutableString stringWithFormat:
	    @"%s %@", of_http_request_method_to_string(method), path];

	if ([URL query] != nil) {
		[requestString appendString: @"?"];
		[requestString appendString: [URL URLEncodedQuery]];
	}

	[requestString appendString: @" HTTP/"];
	[requestString appendString: [request protocolVersionString]];
	[requestString appendString: @"\r\n"];

	headers = [[[request headers] mutableCopy] autorelease];
	if (headers == nil)
		headers = [OFMutableDictionary dictionary];

	if ([headers objectForKey: @"Host"] == nil) {
		OFNumber *port = [URL port];

		if (port != nil) {
			OFString *host = [OFString stringWithFormat:
			    @"%@:%@", [URL URLEncodedHost], port];

			[headers setObject: host
				    forKey: @"Host"];
		} else
			[headers setObject: [URL URLEncodedHost]
				    forKey: @"Host"];
	}

	if (([user length] > 0 || [password length] > 0) &&
	    [headers objectForKey: @"Authorization"] == nil) {
		OFMutableData *authorizationData = [OFMutableData data];
		OFString *authorization;

		[authorizationData addItems: [user UTF8String]
				      count: [user UTF8StringLength]];
		[authorizationData addItem: ":"];
		[authorizationData addItems: [password UTF8String]
				      count: [password UTF8StringLength]];

		authorization = [OFString stringWithFormat:
		    @"Basic %@", [authorizationData stringByBase64Encoding]];

		[headers setObject: authorization
			    forKey: @"Authorization"];
	}

	if ([headers objectForKey: @"User-Agent"] == nil)
		[headers setObject: @"Something using ObjFW "
				    @"<https://heap.zone/objfw>"
			    forKey: @"User-Agent"];

	if ([request protocolVersion].major == 1 &&
	    [request protocolVersion].minor == 0 &&
	    [headers objectForKey: @"Connection"] == nil)
		[headers setObject: @"keep-alive"
			    forKey: @"Connection"];

	if ([headers objectForKey: @"Content-Length"] != nil &&
	    [headers objectForKey: @"Content-Type"] == nil)
		[headers setObject: @"application/x-www-form-"
				    @"urlencoded; charset=UTF-8"
			    forKey: @"Content-Type"];

	keyEnumerator = [headers keyEnumerator];
	objectEnumerator = [headers objectEnumerator];

	while ((key = [keyEnumerator nextObject]) != nil &&
	    (object = [objectEnumerator nextObject]) != nil)
		[requestString appendFormat: @"%@: %@\r\n", key, object];

	[requestString appendString: @"\r\n"];

	[requestString retain];

	objc_autoreleasePoolPop(pool);

	return [requestString autorelease];
}

static OF_INLINE void
normalizeKey(char *str_)
{
	unsigned char *str = (unsigned char *)str_;
	bool firstLetter = true;

	while (*str != '\0') {
		if (!of_ascii_isalpha(*str)) {
			firstLetter = true;
			str++;
			continue;
		}

		*str = (firstLetter
		    ? of_ascii_toupper(*str)
		    : of_ascii_tolower(*str));

		firstLetter = false;
		str++;
	}
}

static bool
defaultShouldFollow(of_http_request_method_t method, int statusCode)
{
	bool follow;

	/*
	 * 301, 302 and 307 should only redirect with user confirmation if the
	 * request method is not GET or HEAD. Asking the delegate and getting
	 * true returned is considered user confirmation.
	 */
	if (method == OF_HTTP_REQUEST_METHOD_GET ||
	    method == OF_HTTP_REQUEST_METHOD_HEAD)
		follow = true;
	/* 303 should always be redirected and converted to a GET request. */
	else if (statusCode == 303)
		follow = true;
	else
		follow = false;

	return follow;
}

@implementation OFHTTPClientRequestHandler
- (instancetype)initWithClient: (OFHTTPClient *)client
		       request: (OFHTTPRequest *)request
		     redirects: (unsigned int)redirects
		       context: (id)context
{
	self = [super init];

	@try {
		_client = [client retain];
		_request = [request retain];
		_redirects = redirects;
		_context = [context retain];
		_serverHeaders = [[OFMutableDictionary alloc] init];
	} @catch (id e) {
		[self release];
		@throw e;
	}

	return self;
}

- (void)dealloc
{
	[_client release];
	[_request release];
	[_context release];
	[_version release];
	[_serverHeaders release];

	[super dealloc];
}

- (void)raiseException: (id)exception
{
	[_client close];
	_client->_inProgress = false;

	[_client->_delegate client: _client
	     didEncounterException: exception
			   request: _request
			   context: _context];
}

- (void)createResponseWithSocketOrThrow: (OFTCPSocket *)sock
{
	OFURL *URL = [_request URL];
	OFHTTPClientResponse *response;
	OFString *connectionHeader;
	bool keepAlive;
	OFString *location;

	response = [[[OFHTTPClientResponse alloc] initWithSocket: sock]
	    autorelease];
	[response setProtocolVersionFromString: _version];
	[response setStatusCode: _status];
	[response setHeaders: _serverHeaders];

	connectionHeader = [_serverHeaders objectForKey: @"Connection"];
	if ([_version isEqual: @"1.1"]) {
		if (connectionHeader != nil)
			keepAlive = ([connectionHeader caseInsensitiveCompare:
			    @"close"] != OF_ORDERED_SAME);
		else
			keepAlive = true;
	} else {
		if (connectionHeader != nil)
			keepAlive = ([connectionHeader caseInsensitiveCompare:
			    @"keep-alive"] == OF_ORDERED_SAME);
		else
			keepAlive = false;
	}

	if (keepAlive) {
		[response of_setKeepAlive: true];

		_client->_socket = [sock retain];
		_client->_lastURL = [URL copy];
		_client->_lastWasHEAD =
		    ([_request method] == OF_HTTP_REQUEST_METHOD_HEAD);
		_client->_lastResponse = [response retain];
	}

	/* FIXME: Case-insensitive check of redirect's scheme */
	if (_redirects > 0 && (_status == 301 || _status == 302 ||
	    _status == 303 || _status == 307) &&
	    (location = [_serverHeaders objectForKey: @"Location"]) != nil &&
	    (_client->_insecureRedirectsAllowed ||
	    [[URL scheme] isEqual: @"http"] ||
	    [location hasPrefix: @"https://"])) {
		OFURL *newURL;
		bool follow;

		newURL = [OFURL URLWithString: location
				relativeToURL: URL];

		if ([_client->_delegate respondsToSelector: @selector(client:
		    shouldFollowRedirect:statusCode:request:response:context:)])
			follow = [_client->_delegate client: _client
				       shouldFollowRedirect: newURL
						 statusCode: _status
						    request: _request
						   response: response
						    context: _context];
		else
			follow = defaultShouldFollow(
			    [_request method], _status);

		if (follow) {
			OFDictionary OF_GENERIC(OFString *, OFString *)
			    *headers = [_request headers];
			OFHTTPRequest *newRequest =
			    [[_request copy] autorelease];
			OFMutableDictionary *newHeaders =
			    [[headers mutableCopy] autorelease];

			if (![[newURL host] isEqual: [URL host]])
				[newHeaders removeObjectForKey: @"Host"];

			/*
			 * 303 means the request should be converted to a GET
			 * request before redirection. This also means stripping
			 * the entity of the request.
			 */
			if (_status == 303) {
				OFEnumerator *keyEnumerator, *objectEnumerator;
				id key, object;

				keyEnumerator = [headers keyEnumerator];
				objectEnumerator = [headers objectEnumerator];
				while ((key = [keyEnumerator nextObject]) !=
				    nil &&
				    (object = [objectEnumerator nextObject]) !=
				    nil)
					if ([key hasPrefix: @"Content-"] ||
					    [key hasPrefix: @"Transfer-"])
						[newHeaders
						    removeObjectForKey: key];

				[newRequest setMethod:
				    OF_HTTP_REQUEST_METHOD_GET];
			}

			[newRequest setURL: newURL];
			[newRequest setHeaders: newHeaders];

			_client->_inProgress = false;

			[_client asyncPerformRequest: newRequest
					   redirects: _redirects - 1
					     context: _context];
			return;
		}
	}

	_client->_inProgress = false;

	if (_status / 100 != 2)
		@throw [OFHTTPRequestFailedException
		    exceptionWithRequest: _request
				response: response];

	[_client->_delegate performSelector: @selector(client:didPerformRequest:
						 response:context:)
				 withObject: _client
				 withObject: _request
				 withObject: response
				 withObject: _context
				 afterDelay: 0];
}

- (void)createResponseWithSocket: (OFTCPSocket *)sock
{
	@try {
		[self createResponseWithSocketOrThrow: sock];
	} @catch (id e) {
		[self raiseException: e];
	}
}

- (bool)handleFirstLine: (OFString *)line
{
	/*
	 * It's possible that the write succeeds on a connection that is
	 * keep-alive, but the connection has already been closed by the remote
	 * end due to a timeout. In this case, we need to reconnect.
	 */
	if (line == nil) {
		[self closeAndReconnect];
		return false;
	}

	if (![line hasPrefix: @"HTTP/"] || [line length] < 9 ||
	    [line characterAtIndex: 8] != ' ')
		@throw [OFInvalidServerReplyException exception];

	_version = [[line substringWithRange: of_range(5, 3)] copy];
	if (![_version isEqual: @"1.0"] && ![_version isEqual: @"1.1"])
		@throw [OFUnsupportedVersionException
		    exceptionWithVersion: _version];

	_status = (int)[[line substringWithRange: of_range(9, 3)] decimalValue];

	return true;
}

- (bool)handleServerHeader: (OFString *)line
		    socket: (OFTCPSocket *)sock
{
	OFString *key, *value, *old;
	const char *lineC, *tmp;
	char *keyC;

	if (line == nil)
		@throw [OFInvalidServerReplyException exception];

	if ([line length] == 0) {
		[_serverHeaders makeImmutable];

		if ([_client->_delegate respondsToSelector: @selector(client:
		    didReceiveHeaders:statusCode:request:context:)])
			[_client->_delegate client: _client
				 didReceiveHeaders: _serverHeaders
					statusCode: _status
					   request: _request
					   context: _context];

		[self performSelector: @selector(createResponseWithSocket:)
			   withObject: sock
			   afterDelay: 0];

		return false;
	}

	lineC = [line UTF8String];

	if ((tmp = strchr(lineC, ':')) == NULL)
		@throw [OFInvalidServerReplyException exception];

	if ((keyC = malloc(tmp - lineC + 1)) == NULL)
		@throw [OFOutOfMemoryException
		    exceptionWithRequestedSize: tmp - lineC + 1];

	memcpy(keyC, lineC, tmp - lineC);
	keyC[tmp - lineC] = '\0';
	normalizeKey(keyC);

	@try {
		key = [OFString stringWithUTF8StringNoCopy: keyC
					      freeWhenDone: true];
	} @catch (id e) {
		free(keyC);
		@throw e;
	}

	do {
		tmp++;
	} while (*tmp == ' ');

	value = [OFString stringWithUTF8String: tmp];

	old = [_serverHeaders objectForKey: key];
	if (old != nil)
		value = [old stringByAppendingFormat: @",%@", value];

	[_serverHeaders setObject: value
			   forKey: key];

	return true;
}

- (bool)socket: (OFTCPSocket *)sock
   didReadLine: (OFString *)line
       context: (id)context
     exception: (id)exception
{
	bool ret;

	if (exception != nil) {
		if ([exception isKindOfClass:
		    [OFInvalidEncodingException class]])
			exception = [OFInvalidServerReplyException exception];

		[self raiseException: exception];
		return false;
	}

	@try {
		if (_firstLine) {
			_firstLine = false;
			ret = [self handleFirstLine: line];
		} else
			ret = [self handleServerHeader: line
						socket: sock];
	} @catch (id e) {
		[self raiseException: e];
		ret = false;
	}

	return ret;
}

-  (size_t)socket: (OFTCPSocket *)sock
  didWriteRequest: (const void **)request
	   length: (size_t)length
	  context: (id)context
	exception: (id)exception
{
	if (exception != nil) {
		if ([exception isKindOfClass: [OFWriteFailedException class]] &&
		    ([exception errNo] == ECONNRESET ||
		    [exception errNo] == EPIPE)) {
			/* In case a keep-alive connection timed out */
			[self closeAndReconnect];
			return 0;
		}

		[self raiseException: exception];
		return 0;
	}

	_firstLine = true;

	if ([[_request headers] objectForKey: @"Content-Length"] != nil) {
		OFStream *requestBody = [[[OFHTTPClientRequestBodyStream alloc]
		    initWithHandler: self
			     socket: sock] autorelease];

		if ([_client->_delegate respondsToSelector:
		    @selector(client:wantsRequestBody:request:context:)])
			[_client->_delegate client: _client
				  wantsRequestBody: requestBody
					   request: _request
					   context: _context];

	} else
		[sock asyncReadLineWithTarget: self
				     selector: @selector(socket:didReadLine:
						   context:exception:)
				      context: nil];

	return 0;
}

- (void)handleSocket: (OFTCPSocket *)sock
{
	/*
	 * As a work around for a bug with split packets in lighttpd when using
	 * HTTPS, we construct the complete request in a buffer string and then
	 * send it all at once.
	 *
	 * We do not use the socket's write buffer in case we need to resend
	 * the entire request (e.g. in case a keep-alive connection timed out).
	 */

	@try {
		OFString *requestString = constructRequestString(_request);
		const char *UTF8String = [requestString UTF8String];
		size_t UTF8StringLength = [requestString UTF8StringLength];

		/*
		 * Pass requestString as context to retain it so that the
		 * underlying buffer lives long enough.
		 */
		[sock asyncWriteBuffer: UTF8String
				length: UTF8StringLength
				target: self
			      selector: @selector(socket:didWriteRequest:
					    length:context:exception:)
			       context: requestString];
	} @catch (id e) {
		[self raiseException: e];
		return;
	}
}

- (void)socketDidConnect: (OFTCPSocket *)sock
		 context: (id)context
	       exception: (id)exception
{
	if (exception != nil) {
		[self raiseException: exception];
		return;
	}

	if ([_client->_delegate respondsToSelector:
	    @selector(client:didCreateSocket:request:context:)])
		[_client->_delegate client: _client
			   didCreateSocket: sock
				   request: _request
				   context: _context];

	[self performSelector: @selector(handleSocket:)
		   withObject: sock
		   afterDelay: 0];
}

- (bool)throwAwayContent: (OFHTTPClientResponse *)response
		  buffer: (char *)buffer
		  length: (size_t)length
		 context: (OFTCPSocket *)sock
	       exception: (id)exception
{
	if (exception != nil) {
		[self raiseException: exception];
		return false;
	}

	if ([response isAtEndOfStream]) {
		[self freeMemory: buffer];

		[_client->_lastResponse release];
		_client->_lastResponse = nil;

		[self performSelector: @selector(handleSocket:)
			   withObject: sock
			   afterDelay: 0];
		return false;
	}

	return true;
}

- (void)start
{
	OFURL *URL = [_request URL];
	OFTCPSocket *sock;

	/* Can we reuse the last socket? */
	if (_client->_socket != nil && ![_client->_socket isAtEndOfStream] &&
	    [[_client->_lastURL scheme] isEqual: [URL scheme]] &&
	    [[_client->_lastURL host] isEqual: [URL host]] &&
	    [_client->_lastURL port] == [URL port]) {
		/*
		 * Set _socket to nil, so that in case of an error it won't be
		 * reused. If everything is successful, we set _socket again
		 * at the end.
		 */
		sock = [_client->_socket autorelease];
		_client->_socket = nil;

		[_client->_lastURL release];
		_client->_lastURL = nil;

		if (!_client->_lastWasHEAD &&
		    ![_client->_lastResponse isAtEndOfStream]) {
			/* Throw away content that has not been read yet */
			char *buffer = [self allocMemoryWithSize: 512];

			[_client->_lastResponse
			    asyncReadIntoBuffer: buffer
					 length: 512
					 target: self
				       selector: @selector(throwAwayContent:
						     buffer:length:context:
						     exception:)
					context: sock];
		} else {
			[_client->_lastResponse release];
			_client->_lastResponse = nil;

			[self performSelector: @selector(handleSocket:)
				   withObject: sock
				   afterDelay: 0];
		}
	} else
		[self closeAndReconnect];
}

- (void)closeAndReconnect
{
	@try {
		OFURL *URL = [_request URL];
		OFTCPSocket *sock;
		uint16_t port;
		OFNumber *URLPort;

		[_client close];

		if ([[URL scheme] isEqual: @"https"]) {
			if (of_tls_socket_class == Nil)
				@throw [OFUnsupportedProtocolException
				    exceptionWithURL: URL];

			sock = [[[of_tls_socket_class alloc] init] autorelease];
			port = 443;
		} else {
			sock = [OFTCPSocket socket];
			port = 80;
		}

		URLPort = [URL port];
		if (URLPort != nil)
			port = [URLPort uInt16Value];

		[sock asyncConnectToHost: [URL host]
				    port: port
				  target: self
				selector: @selector(socketDidConnect:context:
					      exception:)
				 context: nil];
	} @catch (id e) {
		[self raiseException: e];
	}
}
@end

@implementation OFHTTPClientRequestBodyStream
- (instancetype)initWithHandler: (OFHTTPClientRequestHandler *)handler
			 socket: (OFTCPSocket *)sock
{
	self = [super init];

	@try {
		OFDictionary OF_GENERIC(OFString *, OFString *) *headers;
		intmax_t contentLength;
		OFString *contentLengthString;

		_handler = [handler retain];
		_socket = [sock retain];

		headers = [_handler->_request headers];

		contentLengthString = [headers objectForKey: @"Content-Length"];
		if (contentLengthString == nil)
			@throw [OFInvalidArgumentException exception];

		contentLength = [contentLengthString decimalValue];
		if (contentLength < 0)
			@throw [OFOutOfRangeException exception];

		_toWrite = contentLength;

		if ([headers objectForKey: @"Transfer-Encoding"] != nil)
			@throw [OFInvalidArgumentException exception];
	} @catch (id e) {
		[self release];
		@throw e;
	}

	return self;
}

- (void)dealloc
{
	[self close];

	[_handler release];
	[_socket release];

	[super dealloc];
}

- (size_t)lowlevelWriteBuffer: (const void *)buffer
		       length: (size_t)length
{
	size_t requestedLength = length;
	size_t ret;

	if (_socket == nil)
		@throw [OFNotOpenException exceptionWithObject: self];

	if (_atEndOfStream)
		@throw [OFWriteFailedException
		    exceptionWithObject: self
			requestedLength: requestedLength
			   bytesWritten: 0
				  errNo: 0];

	if (length > _toWrite)
		length = (size_t)_toWrite;

	ret = [_socket writeBuffer: buffer
			    length: length];

	if (ret > length)
		@throw [OFOutOfRangeException exception];

	_toWrite -= ret;

	if (_toWrite == 0)
		_atEndOfStream = true;

	if (requestedLength > length)
		@throw [OFWriteFailedException
		    exceptionWithObject: self
			requestedLength: requestedLength
			   bytesWritten: ret
				  errNo: 0];

	return ret;
}

- (bool)lowlevelIsAtEndOfStream
{
	return _atEndOfStream;
}

- (void)close
{
	if (_socket == nil)
		return;

	if (_toWrite > 0)
		@throw [OFTruncatedDataException exception];

	[_socket asyncReadLineWithTarget: _handler
				selector: @selector(socket:didReadLine:context:
					      exception:)
				 context: nil];

	[_socket release];
	_socket = nil;
}

- (int)fileDescriptorForWriting
{
	return [_socket fileDescriptorForWriting];
}
@end

@implementation OFHTTPClientResponse
@synthesize of_keepAlive = _keepAlive;

- (instancetype)initWithSocket: (OFTCPSocket *)sock
{
	self = [super init];

	_socket = [sock retain];

	return self;
}

- (void)dealloc
{
	[_socket release];

	[super dealloc];
}

- (void)setHeaders: (OFDictionary *)headers
{
	OFString *contentLength;

	[super setHeaders: headers];

	_chunked = [[headers objectForKey: @"Transfer-Encoding"]
	    isEqual: @"chunked"];

	contentLength = [headers objectForKey: @"Content-Length"];
	if (contentLength != nil) {
		_hasContentLength = true;

		@try {
			intmax_t toRead = [contentLength decimalValue];

			if (toRead < 0)
				@throw [OFInvalidServerReplyException
				    exception];

			_toRead = toRead;
		} @catch (OFInvalidFormatException *e) {
			@throw [OFInvalidServerReplyException exception];
		}
	}
}

- (size_t)lowlevelReadIntoBuffer: (void *)buffer
			  length: (size_t)length
{
	if (_socket == nil)
		@throw [OFNotOpenException exceptionWithObject: self];

	if (_atEndOfStream)
		return 0;

	if (!_hasContentLength && !_chunked)
		return [_socket readIntoBuffer: buffer
					length: length];

	if ([_socket isAtEndOfStream])
		@throw [OFTruncatedDataException exception];

	/* Content-Length */
	if (!_chunked) {
		size_t ret;

		if (length > _toRead)
			length = (size_t)_toRead;

		ret = [_socket readIntoBuffer: buffer
				       length: length];

		if (ret > length)
			@throw [OFOutOfRangeException exception];

		_toRead -= ret;

		if (_toRead == 0) {
			_atEndOfStream = true;

			if (!_keepAlive) {
				[_socket release];
				_socket = nil;
			}
		}

		return ret;
	}

	/* Chunked */
	if (_toRead > 0) {
		if (length > _toRead)
			length = (size_t)_toRead;

		length = [_socket readIntoBuffer: buffer
					  length: length];

		_toRead -= length;

		if (_toRead == 0)
			if ([[_socket readLine] length] > 0)
				@throw [OFInvalidServerReplyException
				    exception];

		return length;
	} else {
		void *pool = objc_autoreleasePoolPush();
		OFString *line;
		of_range_t range;

		@try {
			line = [_socket readLine];
		} @catch (OFInvalidEncodingException *e) {
			@throw [OFInvalidServerReplyException exception];
		}

		range = [line rangeOfString: @";"];
		if (range.location != OF_NOT_FOUND)
			line = [line substringWithRange:
			    of_range(0, range.location)];

		@try {
			intmax_t toRead = [line hexadecimalValue];

			if (toRead < 0)
				@throw [OFOutOfRangeException exception];

			_toRead = toRead;
		} @catch (OFInvalidFormatException *e) {
			@throw [OFInvalidServerReplyException exception];
		}

		if (_toRead == 0) {
			_atEndOfStream = true;

			if (_keepAlive) {
				@try {
					line = [_socket readLine];
				} @catch (OFInvalidEncodingException *e) {
					@throw [OFInvalidServerReplyException
					    exception];
				}

				if ([line length] > 0)
					@throw [OFInvalidServerReplyException
					    exception];
			} else {
				[_socket release];
				_socket = nil;
			}
		}

		objc_autoreleasePoolPop(pool);

		return 0;
	}
}

- (bool)lowlevelIsAtEndOfStream
{
	if (_atEndOfStream)
		return true;

	if (_socket == nil)
		@throw [OFNotOpenException exceptionWithObject: self];

	if (!_hasContentLength && !_chunked)
		return [_socket isAtEndOfStream];

	return _atEndOfStream;
}

- (int)fileDescriptorForReading
{
	if (_socket == nil)
		return -1;

	return [_socket fileDescriptorForReading];
}

- (bool)hasDataInReadBuffer
{
	return ([super hasDataInReadBuffer] || [_socket hasDataInReadBuffer]);
}

- (void)close
{
	_atEndOfStream = false;

	[_socket release];
	_socket = nil;

	[super close];
}
@end

@implementation OFHTTPClient_SyncPerformer
- (instancetype)initWithClient: (OFHTTPClient *)client
{
	self = [super init];

	@try {
		_client = [client retain];
		_delegate = [client delegate];

		[_client setDelegate: self];
	} @catch (id e) {
		[self release];
		@throw e;
	}

	return self;
}

- (void)dealloc
{
	[_client setDelegate: _delegate];
	[_client release];

	[super dealloc];
}

- (OFHTTPResponse *)performRequest: (OFHTTPRequest *)request
			 redirects: (unsigned int)redirects
			   context: (id)context
{
	[_client asyncPerformRequest: request
			   redirects: redirects
			     context: context];

	[[OFRunLoop currentRunLoop] run];

	return _response;
}

-      (void)client: (OFHTTPClient *)client
  didPerformRequest: (OFHTTPRequest *)request
	   response: (OFHTTPResponse *)response
	    context: (id)context
{
	[[OFRunLoop currentRunLoop] stop];

	[_response release];
	_response = [response retain];

	[_delegate     client: client
	    didPerformRequest: request
		     response: response
		      context: context];
}

-	   (void)client: (OFHTTPClient *)client
  didEncounterException: (id)exception
		request: (OFHTTPRequest *)request
		context: (id)context
{
	/*
	 * Restore the delegate - we're giving up, but not reaching the release
	 * of the autorelease pool that contains us, so resetting it via
	 * -[dealloc] might be too late.
	 */
	[_client setDelegate: _delegate];

	@throw exception;
}

-    (void)client: (OFHTTPClient *)client
  didCreateSocket: (OF_KINDOF(OFTCPSocket *))sock
	  request: (OFHTTPRequest *)request
	  context: (id)context
{
	if ([_delegate respondsToSelector:
	    @selector(client:didCreateSocket:request:context:)])
		[_delegate   client: client
		    didCreateSocket: sock
			    request: request
			    context: context];
}

-     (void)client: (OFHTTPClient *)client
  wantsRequestBody: (OFStream *)body
	   request: (OFHTTPRequest *)request
	   context: (id)context
{
	if ([_delegate respondsToSelector:
	    @selector(client:wantsRequestBody:request:context:)])
		[_delegate    client: client
		    wantsRequestBody: body
			     request: request
			     context: context];
}

-      (void)client: (OFHTTPClient *)client
  didReceiveHeaders: (OFDictionary OF_GENERIC(OFString *, OFString *) *)headers
	 statusCode: (int)statusCode
	    request: (OFHTTPRequest *)request
	    context: (id)context
{
	if ([_delegate respondsToSelector:
	    @selector(client:didReceiveHeaders:statusCode:request:context:)])
		[_delegate     client: client
		    didReceiveHeaders: headers
			   statusCode: statusCode
			      request: request
			      context: context];
}

-	  (bool)client: (OFHTTPClient *)client
  shouldFollowRedirect: (OFURL *)URL
	    statusCode: (int)statusCode
	       request: (OFHTTPRequest *)request
	      response: (OFHTTPResponse *)response
	       context: (id)context
{
	if ([_delegate respondsToSelector: @selector(client:
	    shouldFollowRedirect:statusCode:request:response:context:)])
		return [_delegate client: client
		    shouldFollowRedirect: URL
			      statusCode: statusCode
				 request: request
				response: response
				 context: context];
	else
		return defaultShouldFollow([request method], statusCode);
}
@end

@implementation OFHTTPClient
@synthesize delegate = _delegate;
@synthesize insecureRedirectsAllowed = _insecureRedirectsAllowed;

+ (instancetype)client
{
	return [[[self alloc] init] autorelease];
}

- (void)dealloc
{
	[self close];

	[super dealloc];
}

- (OFHTTPResponse *)performRequest: (OFHTTPRequest *)request
{
	return [self performRequest: request
			  redirects: REDIRECTS_DEFAULT
			    context: nil];
}

- (OFHTTPResponse *)performRequest: (OFHTTPRequest *)request
			 redirects: (unsigned int)redirects
{
	return [self performRequest: request
			  redirects: redirects
			    context: nil];
}

- (OFHTTPResponse *)performRequest: (OFHTTPRequest *)request
			   context: (id)context
{
	return [self performRequest: request
			  redirects: REDIRECTS_DEFAULT
			    context: context];
}

- (OFHTTPResponse *)performRequest: (OFHTTPRequest *)request
			 redirects: (unsigned int)redirects
			   context: (id)context
{
	void *pool = objc_autoreleasePoolPush();
	OFHTTPClient_SyncPerformer *syncPerformer =
	    [[[OFHTTPClient_SyncPerformer alloc] initWithClient: self]
	    autorelease];
	OFHTTPResponse *response = [syncPerformer performRequest: request
						       redirects: redirects
							 context: context];

	[response retain];

	objc_autoreleasePoolPop(pool);

	return [response autorelease];
}

- (void)asyncPerformRequest: (OFHTTPRequest *)request
		    context: (id)context
{
	[self asyncPerformRequest: request
			redirects: REDIRECTS_DEFAULT
			  context: context];
}

- (void)asyncPerformRequest: (OFHTTPRequest *)request
		  redirects: (unsigned int)redirects
		    context: (id)context
{
	void *pool = objc_autoreleasePoolPush();
	OFURL *URL = [request URL];
	OFString *scheme = [URL scheme];

	if (![scheme isEqual: @"http"] && ![scheme isEqual: @"https"])
		@throw [OFUnsupportedProtocolException exceptionWithURL: URL];

	if (_inProgress)
		/* TODO: Find a better exception */
		@throw [OFAlreadyConnectedException exception];

	_inProgress = true;

	[[[[OFHTTPClientRequestHandler alloc]
	    initWithClient: self
		   request: request
		 redirects: redirects
		   context: context] autorelease] start];

	objc_autoreleasePoolPop(pool);
}

- (void)close
{
	[_socket release];
	_socket = nil;

	[_lastURL release];
	_lastURL = nil;

	[_lastResponse release];
	_lastResponse = nil;
}
@end