ObjFW  Artifact [6bac196b77]

Artifact 6bac196b770704570631dec24a1706b102bd27351a8e54d75929b7c8d8d1c2d3:

• File utils/ofhttp/OFHTTP.m — part of check-in [d30efa8bbf] at 2021-11-13 13:04:13 on branch trunk — Completely rework the TLS/SSL API

  The previous API could never work cleanly and would always require
  hacks, as it needed intercepting all interactions of OFTCPSocket with
  the raw socket and did not work at all if the OFTCPSocket had anything
  in its read buffer before starting the TLS handshake. This also could
  not be fixed easily, as it would have required the object to contain two
  read buffers, one for the unencrypted connection and one for the
  encrypted connection. There was also no clean way to perform the
  handshake in a non-blocking way.

  The new API is a lot cleaner and requires none of the hacks, but using
  it requires slightly more work. But this is more than made up for by
  making a fully asynchronous handshake possible. It uses the concept of a
  stream wrapping another stream, meaning the entire connecting part is
  being handled by OFTCPSocket and then the connected socket is passed off
  to OFTLSStream to wrap it. This also makes for a lot cleaner separation
  of concerns. (user: js, size: 29663) [annotate] [blame] [check-ins using]

/*
 * Copyright (c) 2008-2021 Jonathan Schleifer <js@nil.im>
 *
 * 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.
 */

#include "config.h"

#import "OFApplication.h"
#import "OFArray.h"
#import "OFData.h"
#import "OFDictionary.h"
#import "OFFile.h"
#import "OFFileManager.h"
#import "OFHTTPClient.h"
#import "OFHTTPRequest.h"
#import "OFHTTPResponse.h"
#import "OFLocale.h"
#import "OFOptionsParser.h"
#ifdef OF_HAVE_PLUGINS
# import "OFPlugin.h"
#endif
#import "OFSandbox.h"
#import "OFStdIOStream.h"
#import "OFSystemInfo.h"
#import "OFTCPSocket.h"
#import "OFTLSStream.h"
#import "OFURL.h"

#import "OFConnectionFailedException.h"
#import "OFHTTPRequestFailedException.h"
#import "OFInvalidArgumentException.h"
#import "OFInvalidFormatException.h"
#import "OFInvalidServerReplyException.h"
#import "OFOpenItemFailedException.h"
#import "OFOutOfRangeException.h"
#import "OFReadFailedException.h"
#import "OFResolveHostFailedException.h"
#import "OFRetrieveItemAttributesFailedException.h"
#import "OFUnsupportedProtocolException.h"
#import "OFWriteFailedException.h"

#import "ProgressBar.h"

#define GIBIBYTE (1024 * 1024 * 1024)
#define MEBIBYTE (1024 * 1024)
#define KIBIBYTE (1024)

@interface OFHTTP: OFObject <OFApplicationDelegate, OFHTTPClientDelegate,
    OFStreamDelegate>
{
	OFArray OF_GENERIC(OFString *) *_URLs;
	size_t _URLIndex;
	int _errorCode;
	OFString *_outputPath, *_currentFileName;
	bool _continue, _force, _detectFileName, _detectFileNameRequest;
	bool _detectedFileName, _quiet, _verbose, _insecure, _ignoreStatus;
	bool _useUnicode;
	OFStream *_body;
	OFHTTPRequestMethod _method;
	OFMutableDictionary *_clientHeaders;
	OFHTTPClient *_HTTPClient;
	char *_buffer;
	OFStream *_output;
	unsigned long long _received, _length, _resumedFrom;
	ProgressBar *_progressBar;
}

- (void)downloadNextURL;
@end

OF_APPLICATION_DELEGATE(OFHTTP)

static void
help(OFStream *stream, bool full, int status)
{
	[OFStdErr writeLine:
	    OF_LOCALIZED(@"usage",
	    @"Usage: %[prog] -[cehHmoOPqv] url1 [url2 ...]",
	    @"prog", [OFApplication programName])];

	if (full) {
		[stream writeString: @"\n"];
		[stream writeLine: OF_LOCALIZED(@"full_usage",
		    @"Options:\n    "
		    @"-b  --body           "
		    @"  Specify the file to send as body\n    "
		    @"                     "
		    @"  (- for standard input)\n    "
		    @"-c  --continue       "
		    @"  Continue download of existing file\n    "
		    @"-f  --force          "
		    @"  Force / overwrite existing file\n    "
		    @"-h  --help           "
		    @"  Show this help\n    "
		    @"-H  --header         "
		    @"  Add a header (e.g. X-Foo:Bar)\n    "
		    @"-m  --method         "
		    @"  Set the method of the HTTP request\n    "
		    @"-o  --output         "
		    @"  Specify output file name\n    "
		    @"-O  --detect-filename"
		    @"  Do a HEAD request to detect the file name\n    "
		    @"-P  --proxy          "
		    @"  Specify SOCKS5 proxy\n    "
		    @"-q  --quiet          "
		    @"  Quiet mode (no output, except errors)\n    "
		    @"-v  --verbose        "
		    @"  Verbose mode (print headers)\n    "
		    @"    --insecure       "
		    @"  Ignore TLS errors and allow insecure redirects\n    "
		    @"    --ignore-status  "
		    @"  Ignore HTTP status code")];
	}

	[OFApplication terminateWithStatus: status];
}

static OFString *
fileNameFromContentDisposition(OFString *contentDisposition)
{
	void *pool;
	const char *UTF8String;
	size_t UTF8StringLength;
	enum {
		stateDispositionType,
		stateDispositionTypeSemicolon,
		stateDispositionParamNameSkipSpace,
		stateDispositionParamName,
		stateDispositionParamValue,
		stateDispositionParamQuoted,
		stateDispositionParamUnquoted,
		stateDispositionExpectSemicolon
	} state;
	size_t last;
	OFString *type = nil, *paramName = nil, *paramValue;
	OFMutableDictionary *params;
	OFString *fileName;

	if (contentDisposition == nil)
		return nil;

	pool = objc_autoreleasePoolPush();

	UTF8String = contentDisposition.UTF8String;
	UTF8StringLength = contentDisposition.UTF8StringLength;
	state = stateDispositionType;
	params = [OFMutableDictionary dictionary];
	last = 0;

	for (size_t i = 0; i < UTF8StringLength; i++) {
		switch (state) {
		case stateDispositionType:
			if (UTF8String[i] == ';' || UTF8String[i] == ' ') {
				type = [OFString
				    stringWithUTF8String: UTF8String
						  length: i];

				state = (UTF8String[i] == ';'
				    ? stateDispositionParamNameSkipSpace
				    : stateDispositionTypeSemicolon);
				last = i + 1;
			}
			break;
		case stateDispositionTypeSemicolon:
			if (UTF8String[i] == ';') {
				state = stateDispositionParamNameSkipSpace;
				last = i + 1;
			} else if (UTF8String[i] != ' ') {
				objc_autoreleasePoolPop(pool);
				return nil;
			}
			break;
		case stateDispositionParamNameSkipSpace:
			if (UTF8String[i] != ' ') {
				state = stateDispositionParamName;
				last = i;
				i--;
			}
			break;
		case stateDispositionParamName:
			if (UTF8String[i] == '=') {
				paramName = [OFString
				    stringWithUTF8String: UTF8String + last
						  length: i - last];

				state = stateDispositionParamValue;
			}
			break;
		case stateDispositionParamValue:
			if (UTF8String[i] == '"') {
				state = stateDispositionParamQuoted;
				last = i + 1;
			} else {
				state = stateDispositionParamUnquoted;
				last = i;
				i--;
			}
			break;
		case stateDispositionParamQuoted:
			if (UTF8String[i] == '"') {
				paramValue = [OFString
				    stringWithUTF8String: UTF8String + last
						  length: i - last];

				[params setObject: paramValue
					   forKey: paramName.lowercaseString];

				state = stateDispositionExpectSemicolon;
			}
			break;
		case stateDispositionParamUnquoted:
			if (UTF8String[i] <= 31 || UTF8String[i] >= 127)
				return nil;

			switch (UTF8String[i]) {
			case ' ': case '"': case '(': case ')': case ',':
			case '/': case ':': case '<': case '=': case '>':
			case '?': case '@': case '[': case '\\': case ']':
			case '{': case '}':
				return nil;
			case ';':
				paramValue = [OFString
				    stringWithUTF8String: UTF8String + last
						  length: i - last];

				[params setObject: paramValue
					   forKey: paramName.lowercaseString];

				state = stateDispositionParamNameSkipSpace;
				break;
			}
			break;
		case stateDispositionExpectSemicolon:
			if (UTF8String[i] == ';') {
				state = stateDispositionParamNameSkipSpace;
				last = i + 1;
			} else if (UTF8String[i] != ' ') {
				objc_autoreleasePoolPop(pool);
				return nil;
			}
			break;
		}
	}

	if (state == stateDispositionParamUnquoted) {
		paramValue = [OFString
		    stringWithUTF8String: UTF8String + last
				  length: UTF8StringLength - last];

		[params setObject: paramValue
			   forKey: paramName.lowercaseString];
	} else if (state != stateDispositionExpectSemicolon) {
		objc_autoreleasePoolPop(pool);
		return nil;
	}

	if (![type isEqual: @"attachment"] ||
	    (fileName = [params objectForKey: @"filename"]) == nil) {
		objc_autoreleasePoolPop(pool);
		return nil;
	}

	fileName = fileName.lastPathComponent;

	[fileName retain];
	objc_autoreleasePoolPop(pool);
	return [fileName autorelease];
}

@implementation OFHTTP
- (instancetype)init
{
	self = [super init];

	@try {
		_method = OFHTTPRequestMethodGet;

		_clientHeaders = [[OFMutableDictionary alloc]
		    initWithObject: @"OFHTTP"
			    forKey: @"User-Agent"];

		_HTTPClient = [[OFHTTPClient alloc] init];
		_HTTPClient.delegate = self;

		_buffer = OFAllocMemory(1, [OFSystemInfo pageSize]);
	} @catch (id e) {
		[self release];
		@throw e;
	}

	return self;
}

- (void)addHeader: (OFString *)header
{
	size_t pos = [header rangeOfString: @":"].location;
	OFString *name, *value;

	if (pos == OFNotFound) {
		[OFStdErr writeLine: OF_LOCALIZED(@"invalid_input_header",
		    @"%[prog]: Headers must to be in format name:value!",
		    @"prog", [OFApplication programName])];
		[OFApplication terminateWithStatus: 1];
	}

	name = [header substringToIndex: pos]
	    .stringByDeletingEnclosingWhitespaces;

	value = [header substringFromIndex: pos + 1]
	    .stringByDeletingEnclosingWhitespaces;

	[_clientHeaders setObject: value forKey: name];
}

- (void)setBody: (OFString *)path
{
	OFString *contentLength = nil;

	[_body release];
	_body = nil;

	if ([path isEqual: @"-"])
		_body = [OFStdIn copy];
	else {
		_body = [[OFFile alloc] initWithPath: path mode: @"r"];

		@try {
			unsigned long long fileSize =
			    [[OFFileManager defaultManager]
			    attributesOfItemAtPath: path].fileSize;

			contentLength =
			    [OFString stringWithFormat: @"%ju", fileSize];
			[_clientHeaders setObject: contentLength
					   forKey: @"Content-Length"];
		} @catch (OFRetrieveItemAttributesFailedException *e) {
		}
	}

	if (contentLength == nil)
		[_clientHeaders setObject: @"chunked"
				   forKey: @"Transfer-Encoding"];
}

- (void)setMethod: (OFString *)method
{
	void *pool = objc_autoreleasePoolPush();

	method = method.uppercaseString;

	@try {
		_method = OFHTTPRequestMethodParseName(method);
	} @catch (OFInvalidArgumentException *e) {
		[OFStdErr writeLine: OF_LOCALIZED(@"invalid_input_method",
		    @"%[prog]: Invalid request method %[method]!",
		    @"prog", [OFApplication programName],
		    @"method", method)];
		[OFApplication terminateWithStatus: 1];
	}

	objc_autoreleasePoolPop(pool);
}

- (void)setProxy: (OFString *)proxy
{
	@try {
		size_t pos = [proxy
		    rangeOfString: @":"
			  options: OFStringSearchBackwards].location;
		OFString *host;
		unsigned long long port;

		if (pos == OFNotFound)
			@throw [OFInvalidFormatException exception];

		host = [proxy substringToIndex: pos];
		port = [proxy substringFromIndex: pos + 1]
		    .unsignedLongLongValue;

		if (port > UINT16_MAX)
			@throw [OFOutOfRangeException exception];

		[OFTCPSocket setSOCKS5Host: host];
		[OFTCPSocket setSOCKS5Port: (uint16_t)port];
	} @catch (OFInvalidFormatException *e) {
		[OFStdErr writeLine: OF_LOCALIZED(@"invalid_input_proxy",
		    @"%[prog]: Proxy must to be in format host:port!",
		    @"prog", [OFApplication programName])];
		[OFApplication terminateWithStatus: 1];
	}
}

- (void)applicationDidFinishLaunching
{
	OFString *outputPath;
	const OFOptionsParserOption options[] = {
		{ 'b', @"body",	1, NULL, NULL },
		{ 'c', @"continue", 0, &_continue, NULL },
		{ 'f', @"force", 0, &_force, NULL },
		{ 'h', @"help",	0, NULL, NULL },
		{ 'H', @"header", 1, NULL, NULL },
		{ 'm', @"method", 1, NULL, NULL },
		{ 'o', @"output", 1, NULL, &outputPath },
		{ 'O', @"detect-filename", 0, &_detectFileName, NULL },
		{ 'P', @"socks5-proxy", 1, NULL, NULL },
		{ 'q', @"quiet", 0, &_quiet, NULL },
		{ 'v', @"verbose", 0, &_verbose, NULL },
		{ '\0', @"insecure", 0, &_insecure, NULL },
		{ '\0', @"ignore-status", 0, &_ignoreStatus, NULL },
		{ '\0', nil, 0, NULL, NULL }
	};
	OFOptionsParser *optionsParser;
	OFUnichar option;

#ifdef OF_HAVE_SANDBOX
	OFSandbox *sandbox = [OFSandbox sandbox];
	sandbox.allowsStdIO = true;
	sandbox.allowsReadingFiles = true;
	sandbox.allowsWritingFiles = true;
	sandbox.allowsCreatingFiles = true;
	sandbox.allowsIPSockets = true;
	sandbox.allowsDNS = true;
	sandbox.allowsUserDatabaseReading = true;
	sandbox.allowsTTY = true;
	/* Dropped after parsing options */
	sandbox.allowsUnveil = true;

	[OFApplication of_activateSandbox: sandbox];
#endif

#ifndef OF_AMIGAOS
	[OFLocale addLanguageDirectory: @LANGUAGE_DIR];
#else
	[OFLocale addLanguageDirectory: @"PROGDIR:/share/ofhttp/lang"];
#endif

	optionsParser = [OFOptionsParser parserWithOptions: options];
	while ((option = [optionsParser nextOption]) != '\0') {
		switch (option) {
		case 'b':
			[self setBody: optionsParser.argument];
			break;
		case 'h':
			help(OFStdOut, true, 0);
			break;
		case 'H':
			[self addHeader: optionsParser.argument];
			break;
		case 'm':
			[self setMethod: optionsParser.argument];
			break;
		case 'P':
			[self setProxy: optionsParser.argument];
			break;
		case ':':
			if (optionsParser.lastLongOption != nil)
				[OFStdErr writeLine:
				    OF_LOCALIZED(@"long_argument_missing",
				    @"%[prog]: Argument for option --%[opt] "
				    @"missing"
				    @"prog", [OFApplication programName],
				    @"opt", optionsParser.lastLongOption)];
			else {
				OFString *optStr = [OFString
				    stringWithFormat: @"%c",
				    optionsParser.lastOption];
				[OFStdErr writeLine:
				    OF_LOCALIZED(@"argument_missing",
				    @"%[prog]: Argument for option -%[opt] "
				    @"missing",
				    @"prog", [OFApplication programName],
				    @"opt", optStr)];
			}

			[OFApplication terminateWithStatus: 1];
			break;
		case '=':
			[OFStdErr writeLine:
			    OF_LOCALIZED(@"option_takes_no_argument",
			    @"%[prog]: Option --%[opt] takes no argument",
			    @"prog", [OFApplication programName],
			    @"opt", optionsParser.lastLongOption)];

			[OFApplication terminateWithStatus: 1];
			break;
		case '?':
			if (optionsParser.lastLongOption != nil)
				[OFStdErr writeLine:
				    OF_LOCALIZED(@"unknown_long_option",
				    @"%[prog]: Unknown option: --%[opt]",
				    @"prog", [OFApplication programName],
				    @"opt", optionsParser.lastLongOption)];
			else {
				OFString *optStr = [OFString
				    stringWithFormat: @"%c",
				    optionsParser.lastOption];
				[OFStdErr writeLine:
				    OF_LOCALIZED(@"unknown_option",
				    @"%[prog]: Unknown option: -%[opt]",
				    @"prog", [OFApplication programName],
				    @"opt", optStr)];
			}

			[OFApplication terminateWithStatus: 1];
			break;
		}
	}

#ifdef OF_HAVE_SANDBOX
	if (outputPath != nil)
		[sandbox unveilPath: outputPath
			permissions: (_continue ? @"rwc" : @"wc")];
	else
		[sandbox unveilPath: [[OFFileManager defaultManager]
					 currentDirectoryPath]
			permissions: (_continue ? @"rwc" : @"wc")];

	/* In case we use OpenSSL for HTTPS later */
	[sandbox unveilPath: @"/etc/ssl" permissions: @"r"];

	sandbox.allowsUnveil = false;
	[OFApplication of_activateSandbox: sandbox];
#endif

	_outputPath = [outputPath copy];
	_URLs = [optionsParser.remainingArguments copy];

	if (_URLs.count < 1)
		help(OFStdErr, false, 1);

	if (_quiet && _verbose) {
		[OFStdErr writeLine: OF_LOCALIZED(@"quiet_xor_verbose",
		    @"%[prog]: -q / --quiet and -v / --verbose are mutually "
		    @"exclusive!",
		    @"prog", [OFApplication programName])];
		[OFApplication terminateWithStatus: 1];
	}

	if (_outputPath != nil && _detectFileName) {
		[OFStdErr writeLine: OF_LOCALIZED(
		    @"output_xor_detect_filename",
		    @"%[prog]: -o / --output and -O / --detect-filename are "
		    @"mutually exclusive!",
		    @"prog", [OFApplication programName])];
		[OFApplication terminateWithStatus: 1];
	}

	if (_outputPath != nil && _URLs.count > 1) {
		[OFStdErr writeLine:
		    OF_LOCALIZED(@"output_only_with_one_url",
		    @"%[prog]: Cannot use -o / --output when more than one URL "
		    @"has been specified!",
		    @"prog", [OFApplication programName])];
		[OFApplication terminateWithStatus: 1];
	}

	if (_insecure)
		_HTTPClient.allowsInsecureRedirects = true;

	_useUnicode = ([OFLocale encoding] == OFStringEncodingUTF8);

	[self performSelector: @selector(downloadNextURL) afterDelay: 0];
}

-	(void)client: (OFHTTPClient *)client
  didCreateTLSStream: (OFTLSStream *)stream
	     request: (OFHTTPRequest *)request
{
	stream.verifiesCertificates = !_insecure;
}

-     (void)client: (OFHTTPClient *)client
  wantsRequestBody: (OFStream *)body
	   request: (OFHTTPRequest *)request
{
	/* TODO: Do asynchronously and print status */
	while (!_body.atEndOfStream) {
		char buffer[4096];
		size_t length = [_body readIntoBuffer: buffer length: 4096];
		[body writeBuffer: buffer length: length];
	}
}

-	  (bool)client: (OFHTTPClient *)client
  shouldFollowRedirect: (OFURL *)URL
	    statusCode: (short)statusCode
	       request: (OFHTTPRequest *)request
	      response: (OFHTTPResponse *)response
{
	if (_verbose) {
		void *pool = objc_autoreleasePoolPush();
		OFDictionary OF_GENERIC(OFString *, OFString *) *headers =
		    response.headers;
		OFEnumerator *keyEnumerator = [headers keyEnumerator];
		OFEnumerator *objectEnumerator = [headers objectEnumerator];
		OFString *key, *object;

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

		objc_autoreleasePoolPop(pool);
	}

	if (!_quiet) {
		if (_useUnicode)
			[OFStdOut writeFormat: @"☇ %@", URL.string];
		else
			[OFStdOut writeFormat: @"< %@", URL.string];
	}

	_length = 0;

	return true;
}

-      (bool)stream: (OFStream *)response
  didReadIntoBuffer: (void *)buffer
	     length: (size_t)length
	  exception: (id)exception
{
	if (exception != nil) {
		OFString *URL;

		[_progressBar stop];
		[_progressBar draw];
		[_progressBar release];
		_progressBar = nil;

		if (!_quiet) {
			[OFStdOut writeString: @"\n  "];
			[OFStdOut writeLine: OF_LOCALIZED(@"download_error",
			    @"Error!")];
		}

		URL = [_URLs objectAtIndex: _URLIndex - 1];
		[OFStdErr writeLine: OF_LOCALIZED(
		    @"download_failed_exception",
		    @"%[prog]: Failed to download <%[url]>!\n"
		    @"  %[exception]",
		    @"prog", [OFApplication programName],
		    @"url", URL,
		    @"exception", exception)];

		_errorCode = 1;
		[self performSelector: @selector(downloadNextURL)
			   afterDelay: 0];
		return false;
	}

	[_output writeBuffer: buffer length: length];

	_received += length;
	[_progressBar setReceived: _received];

	if (response.atEndOfStream) {
		[_progressBar stop];
		[_progressBar draw];
		[_progressBar release];
		_progressBar = nil;

		if (!_quiet) {
			[OFStdOut writeString: @"\n  "];
			[OFStdOut writeLine:
			    OF_LOCALIZED(@"download_done", @"Done!")];
		}

		[self performSelector: @selector(downloadNextURL)
			   afterDelay: 0];
		return false;
	}

	return true;
}

-      (void)client: (OFHTTPClient *)client
  didReceiveHeaders: (OFDictionary OF_GENERIC(OFString *, OFString *) *)headers
	 statusCode: (short)statusCode
	    request: (OFHTTPRequest *)request
{
	if (statusCode != 206)
		_resumedFrom = 0;

	if (!_quiet) {
		OFString *lengthString =
		    [headers objectForKey: @"Content-Length"];
		OFString *type = [headers objectForKey: @"Content-Type"];

		if (_useUnicode)
			[OFStdOut writeFormat: @" ➜ %hd\n", statusCode];
		else
			[OFStdOut writeFormat: @" -> %hd\n", statusCode];

		if (type == nil)
			type = OF_LOCALIZED(@"type_unknown", @"unknown");

		if (lengthString != nil) {
			_length = lengthString.unsignedLongLongValue;

			if (_resumedFrom + _length >= GIBIBYTE) {
				lengthString = [OFString stringWithFormat:
				    @"%,.2f",
				    (float)(_resumedFrom + _length) / GIBIBYTE];
				lengthString = OF_LOCALIZED(@"size_gib",
				    @"%[num] GiB",
				    @"num", lengthString);
			} else if (_resumedFrom + _length >= MEBIBYTE) {
				lengthString = [OFString stringWithFormat:
				    @"%,.2f",
				    (float)(_resumedFrom + _length) / MEBIBYTE];
				lengthString = OF_LOCALIZED(@"size_mib",
				    @"%[num] MiB",
				    @"num", lengthString);
			} else if (_resumedFrom + _length >= KIBIBYTE) {
				lengthString = [OFString stringWithFormat:
				    @"%,.2f",
				    (float)(_resumedFrom + _length) / KIBIBYTE];
				lengthString = OF_LOCALIZED(@"size_kib",
				    @"%[num] KiB",
				    @"num", lengthString);
			} else {
				lengthString = [OFString stringWithFormat:
				    @"%jd", _resumedFrom + _length];
				lengthString = OF_LOCALIZED(@"size_bytes",
				    @"["
				    @"    ["
				    @"        {'num == 1': '1 byte'},"
				    @"        {'': '%[num] bytes'}"
				    @"    ]"
				    @"]".objectByParsingJSON,
				    @"num", lengthString);
			}
		} else
			lengthString =
			    OF_LOCALIZED(@"size_unknown", @"unknown");

		if (_verbose) {
			void *pool = objc_autoreleasePoolPush();
			OFEnumerator OF_GENERIC(OFString *) *keyEnumerator =
			    [headers keyEnumerator];
			OFEnumerator OF_GENERIC(OFString *) *objectEnumerator =
			    [headers objectEnumerator];
			OFString *key, *object;

			if (statusCode / 100 == 2 && _currentFileName != nil) {
				[OFStdOut writeString: @"  "];
				[OFStdOut writeLine: OF_LOCALIZED(
				    @"info_name_unaligned",
				    @"Name: %[name]",
				    @"name", _currentFileName)];
			}

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

			objc_autoreleasePoolPop(pool);
		} else if (statusCode / 100 == 2 && !_detectFileNameRequest) {
			[OFStdOut writeString: @"  "];

			if (_currentFileName != nil)
				[OFStdOut writeLine: OF_LOCALIZED(@"info_name",
				    @"Name: %[name]",
				    @"name", _currentFileName)];

			[OFStdOut writeString: @"  "];
			[OFStdOut writeLine: OF_LOCALIZED(@"info_type",
			    @"Type: %[type]",
			    @"type", type)];
			[OFStdOut writeString: @"  "];
			[OFStdOut writeLine: OF_LOCALIZED(@"info_size",
			    @"Size: %[size]",
			    @"size", lengthString)];
		}
	}
}

-      (void)client: (OFHTTPClient *)client
  didPerformRequest: (OFHTTPRequest *)request
	   response: (OFHTTPResponse *)response
	  exception: (id)exception
{
	if (exception != nil) {
		if ([exception isKindOfClass:
		    [OFResolveHostFailedException class]]) {
			if (!_quiet)
				[OFStdOut writeString: @"\n"];

			[OFStdErr writeLine:
			    OF_LOCALIZED(@"download_resolve_host_failed",
			    @"%[prog]: Failed to download <%[url]>!\n"
			    @"  Failed to resolve host: %[exception]",
			    @"prog", [OFApplication programName],
			    @"url", request.URL.string,
			    @"exception", exception)];
		} else if ([exception isKindOfClass:
		    [OFConnectionFailedException class]]) {
			if (!_quiet)
				[OFStdOut writeString: @"\n"];

			[OFStdErr writeLine:
			    OF_LOCALIZED(@"download_failed_connection_failed",
			    @"%[prog]: Failed to download <%[url]>!\n"
			    @"  Connection failed: %[exception]",
			    @"prog", [OFApplication programName],
			    @"url", request.URL.string,
			    @"exception", exception)];
		} else if ([exception isKindOfClass:
		    [OFInvalidServerReplyException class]]) {
			if (!_quiet)
				[OFStdOut writeString: @"\n"];

			[OFStdErr writeLine: OF_LOCALIZED(
			    @"download_failed_invalid_server_reply",
			    @"%[prog]: Failed to download <%[url]>!\n"
			    @"  Invalid server reply!",
			    @"prog", [OFApplication programName],
			    @"url", request.URL.string)];
		} else if ([exception isKindOfClass:
		    [OFUnsupportedProtocolException class]]) {
			if (!_quiet)
				[OFStdOut writeString: @"\n"];

			[OFStdErr writeLine: OF_LOCALIZED(@"no_tls_support",
			    @"%[prog]: No TLS support in ObjFW!\n"
			    @"  In order to download via HTTPS, you need to "
			    @"either build ObjFW with TLS\n"
			    @"  support or preload a library adding TLS "
			    @"support to ObjFW!",
			    @"prog", [OFApplication programName])];
		} else if ([exception isKindOfClass:
		    [OFReadOrWriteFailedException class]]) {
			OFString *error = OF_LOCALIZED(
			    @"download_failed_read_or_write_failed_any",
			    @"Read or write failed");

			if (!_quiet)
				[OFStdOut writeString: @"\n"];

			if ([exception isKindOfClass:
			    [OFReadFailedException class]])
				error = OF_LOCALIZED(
				    @"download_failed_read_or_write_failed_"
				    @"read",
				    @"Read failed");
			else if ([exception isKindOfClass:
			    [OFWriteFailedException class]])
				error = OF_LOCALIZED(
				    @"download_failed_read_or_write_failed_"
				    @"write",
				    @"Write failed");

			[OFStdErr writeLine: OF_LOCALIZED(
			    @"download_failed_read_or_write_failed",
			    @"%[prog]: Failed to download <%[url]>!\n"
			    @"  %[error]: %[exception]",
			    @"prog", [OFApplication programName],
			    @"url", request.URL.string,
			    @"error", error,
			    @"exception", exception)];
		} else if ([exception isKindOfClass:
		    [OFHTTPRequestFailedException class]]) {
			short statusCode;
			OFString *codeString;

			if (_ignoreStatus) {
				exception = nil;
				goto after_exception_handling;
			}

			statusCode = response.statusCode;
			codeString = [OFString stringWithFormat: @"%hd %@",
			    statusCode, OFHTTPStatusCodeString(statusCode)];
			[OFStdErr writeLine: OF_LOCALIZED(@"download_failed",
			    @"%[prog]: Failed to download <%[url]>!\n"
			    @"  HTTP status code: %[code]",
			    @"prog", [OFApplication programName],
			    @"url", request.URL.string,
			    @"code", codeString)];
		} else
			@throw exception;

		_errorCode = 1;
		[self performSelector: @selector(downloadNextURL)
			   afterDelay: 0];
		return;
	}

after_exception_handling:
	if (_method == OFHTTPRequestMethodHead)
		goto next;

	if (_detectFileNameRequest) {
		_currentFileName = [fileNameFromContentDisposition(
		    [response.headers objectForKey: @"Content-Disposition"])
		    copy];
		_detectedFileName = true;

		/* Handle this URL on the next -[downloadNextURL] call */
		_URLIndex--;

		[self performSelector: @selector(downloadNextURL)
			   afterDelay: 0];
		return;
	}

	if ([_outputPath isEqual: @"-"])
		_output = [OFStdOut copy];
	else {
		if (!_continue && !_force && [[OFFileManager defaultManager]
		    fileExistsAtPath: _currentFileName]) {
			[OFStdErr writeLine:
			    OF_LOCALIZED(@"output_already_exists",
			    @"%[prog]: File %[filename] already exists!",
			    @"prog", [OFApplication programName],
			    @"filename", _currentFileName)];

			_errorCode = 1;
			goto next;
		}

		@try {
			OFString *mode =
			    (response.statusCode == 206 ? @"a" : @"w");
			_output = [[OFFile alloc] initWithPath: _currentFileName
							  mode: mode];
		} @catch (OFOpenItemFailedException *e) {
			[OFStdErr writeLine:
			    OF_LOCALIZED(@"failed_to_open_output",
			    @"%[prog]: Failed to open file %[filename]: "
			    @"%[exception]",
			    @"prog", [OFApplication programName],
			    @"filename", _currentFileName,
			    @"exception", e)];

			_errorCode = 1;
			goto next;
		}
	}

	if (!_quiet) {
		_progressBar = [[ProgressBar alloc]
		    initWithLength: _length
		       resumedFrom: _resumedFrom
			useUnicode: _useUnicode];
		[_progressBar setReceived: _received];
		[_progressBar draw];
	}

	[_currentFileName release];
	_currentFileName = nil;

	response.delegate = self;
	[response asyncReadIntoBuffer: _buffer length: [OFSystemInfo pageSize]];
	return;

next:
	[_currentFileName release];
	_currentFileName = nil;

	[self performSelector: @selector(downloadNextURL) afterDelay: 0];
}

- (void)downloadNextURL
{
	OFString *URLString = nil;
	OFURL *URL;
	OFMutableDictionary *clientHeaders;
	OFHTTPRequest *request;

	_received = _length = _resumedFrom = 0;

	if (_output != OFStdOut)
		[_output release];
	_output = nil;

	if (_URLIndex >= _URLs.count)
		[OFApplication terminateWithStatus: _errorCode];

	@try {
		URLString = [_URLs objectAtIndex: _URLIndex++];
		URL = [OFURL URLWithString: URLString];
	} @catch (OFInvalidFormatException *e) {
		[OFStdErr writeLine: OF_LOCALIZED(@"invalid_url",
		    @"%[prog]: Invalid URL: <%[url]>!",
		    @"prog", [OFApplication programName],
		    @"url", URLString)];

		_errorCode = 1;
		goto next;
	}

	if (![URL.scheme isEqual: @"http"] && ![URL.scheme isEqual: @"https"]) {
		[OFStdErr writeLine: OF_LOCALIZED(@"invalid_scheme",
		    @"%[prog]: Invalid scheme: <%[url]>!",
		    @"prog", [OFApplication programName],
		    @"url", URLString)];

		_errorCode = 1;
		goto next;
	}

	clientHeaders = [[_clientHeaders mutableCopy] autorelease];

	if (_detectFileName && !_detectedFileName) {
		if (!_quiet) {
			if (_useUnicode)
				[OFStdOut writeFormat: @"⠒ %@", URL.string];
			else
				[OFStdOut writeFormat: @"? %@", URL.string];
		}

		request = [OFHTTPRequest requestWithURL: URL];
		request.headers = clientHeaders;
		request.method = OFHTTPRequestMethodHead;

		_detectFileNameRequest = true;
		[_HTTPClient asyncPerformRequest: request];
		return;
	}

	if (!_detectedFileName) {
		[_currentFileName release];
		_currentFileName = nil;
	} else
		_detectedFileName = false;

	if (_currentFileName == nil)
		_currentFileName = [_outputPath copy];

	if (_currentFileName == nil)
		_currentFileName = [URL.path.lastPathComponent copy];

	if ([_currentFileName isEqual: @"/"]) {
		[_currentFileName release];
		_currentFileName = nil;
	}

	if (_currentFileName == nil)
		_currentFileName = @"unnamed";

	if (_continue) {
		@try {
			unsigned long long size =
			    [[OFFileManager defaultManager]
			    attributesOfItemAtPath: _currentFileName].fileSize;
			OFString *range;

			if (size > ULLONG_MAX)
				@throw [OFOutOfRangeException exception];

			_resumedFrom = (unsigned long long)size;

			range = [OFString stringWithFormat: @"bytes=%jd-",
							    _resumedFrom];
			[clientHeaders setObject: range forKey: @"Range"];
		} @catch (OFRetrieveItemAttributesFailedException *e) {
		}
	}

	if (!_quiet) {
		if (_useUnicode)
			[OFStdOut writeFormat: @"⇣ %@", URL.string];
		else
			[OFStdOut writeFormat: @"< %@", URL.string];
	}

	request = [OFHTTPRequest requestWithURL: URL];
	request.headers = clientHeaders;
	request.method = _method;

	_detectFileNameRequest = false;
	[_HTTPClient asyncPerformRequest: request];
	return;

next:
	[self performSelector: @selector(downloadNextURL) afterDelay: 0];
}
@end