path: root/lib/HttpServ.cc

/*
 *  Baltisot
 *  Copyright (C) 1999-2007 Nicolas "Pixel" Noble
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/* $Id: HttpServ.cc,v 1.60 2008-01-28 17:09:18 pixel Exp $ */

#include <vector>

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "Socket.h"
#include "Action.h"
#include "HttpServ.h"
#include "Buffer.h"
#include "ReadJob.h"
#include "CopyJob.h"
#include "ChainTasks.h"
#include "Task.h"
#include "Base64.h"
#include "Domain.h"
#include "HashFunction.h"
#include "gettext.h"

#define MAXLEN 4*1024*1024

/*
 stuff we should support...
 
 Etags:
  Server: ETag: "27b42a-134-46cece08"
  Client: If-None-Match: "27b42a-146-46cecd32"
 
 Last-Modified: 
  Server: Last-Modified: Fri, 24 Aug 2007 12:24:40 GMT
  Client: If-Modified-Since: Fri, 24 Aug 2007 12:21:06 GMT
  
 Multipart stuff:

----8<-----Example-------8<--------
Content-Type: multipart/form-data; boundary=---------------------------163944935918044553841983937859
Content-Length: 377

-----------------------------163944935918044553841983937859
Content-Disposition: form-data; name="textline"


-----------------------------163944935918044553841983937859
Content-Disposition: form-data; name="datafile"; filename="tst-user-agent.txt"
Content-Type: text/plain

User-Agent: CFNetwork/129.20

-----------------------------163944935918044553841983937859--
----8<-----Example-------8<--------

*/
  
  

String endhl = "\r\n", endnl = "\n";

struct multipart_file {
      multipart_file(Buffer * _file, const String & _type, const String & _filename, const String & _varname) : file(_file), type(_type), filename(_filename), varname(_varname) { }
      ~multipart_file() { }
    Buffer * file;
    String type, filename, varname;
};

typedef std::vector<struct multipart_file> multipart_files;

class ProcessRequest : public Task {
  public:
      ProcessRequest(Action * action, const Socket & out, const String & server_name, int server_port, const String & root = "/bin/start");
      virtual ~ProcessRequest();
    virtual String GetName();
  protected:
    virtual int Do() throw (GeneralException);
  private:
    String GetMime(const String &);
    String UnMangle(const String &, int p = 0);
    bool ParseUri(String &, String &, String &, Handle *);
    void ParseVars(Handle *, int);
    void ParseMultipart(Handle *, int);
    void ShowError(Handle *);
    void SendHeads(Handle *, const String &, const String & = "", time_t = -1);
    void SendRedirect(Handle *);

    String file, domain, t, Method, Uri;
    Buffer b;
    Task * c, * a;
    Action * f;
    int len, localport;
    Action * p;
    Socket s;
    Domain * d;
    
    multipart_files m_files;
    
    String name, host, gvars, login, password, root, boundary;
    Variables * Vars, * Heads;
    bool bad, hasvars, post, multipart, content_type;
    
    HttpResponse response;
};

ProcessRequest::ProcessRequest(Action * ap, const Socket & as, const String & aname, int aport, const String & aroot) : localport(aport), p(ap), s(as), name(aname), root(aroot) {
    SetBurst();
}

ProcessRequest::~ProcessRequest() {
    std::vector<struct multipart_file>::iterator i;
    
    for (i = m_files.begin(); i != m_files.end(); i++) {
        delete i->file;
    }
}

String ProcessRequest::GetName() {
    return _("Processing HTTP request");
}

int ProcessRequest::Do() throw(GeneralException) {
    switch (current) {
    case 0:
        if (!s.IsConnected()) return TASK_DONE;

        c = new ReadJob(&s, &b);
        WaitFor(c);
	current = 1;
        Suspend(TASK_ON_HOLD);

    case 1:
        delete c;

        bad = false;

//	std::cerr << "---- Got a request from handle " << s.GetHandle() << " \n";
    
        post = ParseUri(file, domain, gvars, &b);
	
	Heads = new Variables();
	Vars = new Variables();

        len = -1;
        content_type = false;
        do {
	    int p;
    	    b >> t;
//	    std::cerr << "Read Request (n): " << t << std::endl;
	    if ((t.strstr("Content-Length: ") == 0) || (t.strstr("Content-length: ") == 0)) {
//		std::cerr << "Saw 'Content-Lenght:', reading length from '" << t.extract(16) << "'\n";
	        len = t.extract(16).to_int();
                if (len > MAXLEN)
                    len = -1;
	    }
	    if (t.strstr("Host: ") == 0) {
		host = t.extract(6);
	    }
            if (t.strstr("Authorization: Basic ") == 0) {
                int l;
                char * credentials = (char *) Base64::decode(t.extract(21), &l);
                credentials[l] = 0;
                char * p = strchr(credentials, ':');

                if (p) {
                    *p = 0;
                    login = credentials;
                    password = p + 1;
                }
                
                free(credentials);
            }
            if (t.strstr("Content-Type: application/x-www-form-urlencoded") == 0) {
                // basic post method
                multipart = false;
                content_type = true;
            }
            if (t.strstr("Content-Type: multipart/form-data; boundary=") == 0) {
                multipart = true;
                content_type = true;
                boundary = "--" + t.extract(44);
            }
	    
	    if ((p = t.strchr(':')) >= 0) {
		String s = t.extract(0, p - 1);
		s += '=';
		s += t.extract(p + 2);
		Heads->Add(s);
	    }
	} while (t.strlen());
	
//	std::cerr << "---- Processing it.\n";

        hasvars = false;

	if (post) {
	    // On a pas eu de ligne 'Content-Length' mais on a eu une méthode POST.
	    // Cela est une erreur.
	    if (len == -1) {
//		std::cerr << "Error: method POST but no Content-Length\n";
		bad = true;
	    } else {
//		std::cerr << "Got a POST request. Parsing variables. (len = " << len << ")\n";
	        // Les variables seront initialisées ici.
		hasvars = true;
	    }
            
            if (!content_type) {
                bad = true;
            }
	}

	current = 2;
	if (hasvars && len) {
	    c = new CopyJob(&s, &b, len);
	    WaitFor(c);
	    Suspend();
        } else {
	    c = 0;
	}

    case 2:
	if (gvars != "") {
	    Buffer b2;
	    b2 << gvars;
	    ParseVars(&b2, gvars.strlen());
	}
	if (hasvars && len) {
            delete c;
            if (!multipart) {
	        ParseVars(&b, len);
            } else {
                ParseMultipart(&b, len);
            }
	}
    
	std::cerr << " Domain = '" << domain << "' - File = '" << file << "'\n";

        if (file == "favicon.ico") {
            domain = "/image";
        }
	
        if (!bad) {
	    // Nous vérifions le domaine.
	    bad = true;
	    // Les domaines par défaut valides sont '/', '/bin' et '/image'.
	    if (domain == "/image") bad = false;
	    if (domain == "/bin") bad = false;
	    if (domain == "/") bad = false;
    	    // L'url sans domaine ni fichier est valide. (cela arrive sur certains navigateurs...)
            if (domain == "") bad = (file != "");
            if ((d = Domain::find_domain(Uri))) bad = false;
	    if (bad) {
	        std::cerr << _("Error: bad domain.\n");
	    }
	}

        a = 0;

	if (bad) {
	    ShowError(&b);
	} else {
	    if (d) {
                HttpRequest request;
                request.vars = Vars;
                request.headers = Heads;
                request.uri = Uri;
                request.login = login;
                request.password = password;
		request.lip = s.GetAddr();
		request.dip = s.GetDistantAddr();
		request.lport = s.GetPort();
		request.dport = s.GetDistantPort();
                request.method = Method;
                d->Do(request, &response);
                a = response.BuildResponse(&s);
	    } else if (((domain == "") || (domain == "/")) && (file == "")) {
		// Si le navigateur a demandé l'URL '/', alors on renvoie une notification
		// de redirection.
		SendRedirect(&b);
	    } else if (domain == "/bin") {
		// Le domaine 'bin' est réservé aux actions. On cherche donc l'action à effectuer.
	        if ((f = p->Look4URL(file))) {
    		    SendHeads(&b, "text/html");
		    a = f->Do(Vars, Heads, &s);
		} else {
		    ShowError(&b);
	        }
	    } else if (domain == "/image") {
		// Dans tous les autres cas de domaine, on cherche le fichier dans le répertoire data.
	        // On utilise try au cas où le fichier n'existe pas et donc que le constructeur
	        // d'input renvoie une erreur.
	        try {
	    	    Handle * i = new Input(String("data/") + file);
	    	    SendHeads(&b, GetMime(file), String("Accept-Ranges: bytes") + endhl + "Content-Length: " + (unsigned long long int) i->GetSize() + endhl, i->GetModif());
		    i->SetNonBlock();
		    a = new CopyJob(i, &s);
		    std::cerr << _("File found, dumping.\n");
		}
	        catch (IOGeneral e) {
		    ShowError(&b);
		    std::cerr << _("File not found, error shown.\n");
		}
            } else {
                ShowError(&b);
            }
	}
    
	if (a) a->Stop();
    
//	std::cerr << "---- Sending header buffer.\n";
        if (!d) {
    	    c = new CopyJob(&b, &s, -1, false);
            WaitFor(c);
	    current = 3;
	    Suspend();
        }

    case 3:
        if (!d)
    	    delete c;
    
	if (a) {
//	    std::cerr << "---- Sending contents.\n";
	    a->Restart();
	    WaitFor(a);
	    current = 4;
	    Suspend();
	}

    case 4:
	if (a) delete a;
	delete Vars;
	delete Heads;
//	std::cerr << "---- End of Request.\n";
    }
    return TASK_DONE;
}

void ProcessRequest::ParseMultipart(Handle * s, int len) {
    String t, crboundary, k, v, disposition, type;
    char redo[256], r, tmp[4];
    int p, i, rl;
    bool done = false, in_headers = true, is_file = false;
    Buffer * out = 0;
    std::vector<struct multipart_file>::iterator mf_p;
    Variables * dispos_headers;
    
    crboundary = "\r\n" + boundary;
    
    redo[0] = p = 0;
    i = 1;
    while (i < crboundary.strlen()) {
        if (crboundary[i] == crboundary[p]) {
            redo[i++] = ++p;
        } else if (p > 0) {
            p = redo[p - 1];
        } else {
            redo[i++] = 0;
        }
    }

    p = 0;
    (*s) >> t;
    if (t != boundary) {
        return;
    }
    while (!done) {
        if (in_headers) {
            (*s) >> t;
            if (t != "") {
                // Content-Disposition: form-data; name="datafile"; filename="tst-user-agent.txt"
                // Content-Type: text/plain
                if (t.strstr("Content-Disposition: form-data; ") == 0) {
                    disposition = t.extract(32);
                    dispos_headers = new Variables();
                    // ****
                } else if (t.strstr("Content-Type: ") == 0) {
                    type = t.extract(14);
                } else {
                    printm(M_WARNING, "Unknown header in multipart chunk: " + t + "\n");
                }
            } else {
                in_headers = false;
                if ((type != "") && ((*dispos_headers)["filename"] != "")) {
                    is_file = true;
                    out = new Buffer();
                } else {
                    k = (*dispos_headers)["name"];
                }
            }
        } else {
            rl = 0;
            
            r = s->readU8();
            if (crboundary[p] == r) {
                p++;
                rl = 1;
            } else {
                for (i = 0; i <= p; i++) {
                    if (is_file) {
                        out->writeU8(crboundary[i]);
                    } else {
                        v += crboundary[i];
                    }
                }
                if (p > 0)
                    p = redo[p - 1];
            }
        
            if (p == crboundary.strlen()) {
                p = 0;
                tmp[0] = s->readU8();
                tmp[1] = s->readU8();
                
                if ((t[0] == 13) && (t[1] == 10)) {
                    in_headers = true;
                    
                    if (is_file) {
                        m_files.push_back(multipart_file(out, type, (*dispos_headers)["filename"], (*dispos_headers)["name"]));
                        out = 0;
                    } else {
                        Vars->Add(k + "=" + v);
                    }
                    
                    k = "";
                    v = "";
                    type = "";
                    delete dispos_headers;
                } else if ((tmp[0] == '-') && (tmp[1] == '-')) {
                    tmp[2] = s->readU8();
                    tmp[3] = s->readU8();
                    if ((tmp[2] == 13) && (tmp[3] == 10)) {                    
                        // end of streams
                        
                        if (is_file) {
                            m_files.push_back(multipart_file(out, type, (*dispos_headers)["filename"], (*dispos_headers)["name"]));
                            out = 0;
                        } else {
                            Vars->Add(k + "=" + v);
                        }
                        return;
                    } else {
                        rl = 4;
                    }
                } else {
                    rl = 2;
                }
            }
            
            for (i = 0; i < rl; i++) {
                if (is_file) {
                    out->writeU8(r);
                } else {
                    v += r;
                }
            
                r = tmp[0];
                tmp[0] = tmp[1];
                tmp[1] = tmp[2];
                tmp[2] = tmp[3];
            }
        }
    }
}

void ProcessRequest::ParseVars(Handle * s, int len) {
    String t, v;
    char conv[3], l;
    int hconv, nbvars;
    ssize_t pos = 0, next;
    
    t = "";
    for (int i = 0; i < len; i++) {
	s->read(&l, 1);
	t += l;
    }
//  std::cerr << "Post variables line: '" << t << "'\n";
    
    
    // Les variables sont sous la forme 'var1=val1&var2=val2&val3=var3'. Donc le nombre d'occurences
    // du caractère '=' indique le nombre de variables.
    
    // WRONG! WRONG!
    nbvars = t.strchrcnt('=');
    
    for (int i = 0; i < nbvars; i++) {
	// Les variables sont sous la forme 'var1=val1&var2=val2&val3=var3'. Donc on cherche le caractère
	// & dans la chaine POST.
	next = t.strchr('&', pos);
	if (next < 0) next = t.strlen();
	v = "";
	while (pos != next) {
	    switch (t[pos]) {
	    // Le navigateur encode les caractères spéciaux à l'aide du format %XX où XX indique
	    // la valeur hexadécimale du caractère. Nous encodons surtout les caractères
	    // ' ', '=', '%', et '/' avec cette technique.
	    case '%':
		pos++;
		conv[0] = t[pos++];
		conv[1] = t[pos++];
		conv[2] = '\0';
		sscanf(conv, "%x", &hconv);
		v += ((char) hconv);
		break;
	    // Certains navigateurs utilisent '+' pour indiquer ' ' (qui est illégal) au lieu
	    // d'utiliser %20.
	    case '+':
		v += ' ';
		pos++;
		break;
	    default:
    		v += t[pos++];
	    }
	}
//	std::cerr << "Pushing HTTP variable: " << v << std::endl;
	Vars->Add(v);
	pos++;
    }
}

/*
 * Cette fonction renverra true si la méthode est une méthode POST.
 * Les Strings domain et file seront modifiées afin de renvoyer le domaine
 * et le fichier lut. La string s doit donner la première ligne de la requète,
 * c'est à dire la méthode demandée par le client.
 */

bool ProcessRequest::ParseUri(String & file, String & domain, String & gvars, Handle * s) {
    String t;
    bool post = false;
    const char * p = 0;
    ssize_t sppos;

    *s >> t;
    std::cerr << _("Read Request (1): ") << t << std::endl;

    int IPos = t.strchr('?');
    
    gvars = "";
    
    if (IPos >= 0) {
	int HPos = t.strchr(' ', IPos);
	char * sdup = t.strdup(0, IPos - 1);
	gvars = t.extract(IPos + 1, HPos - 1);
	t = sdup;
	free(sdup);
    }
    
//  std::cerr << "New request: " << t << ", gvars = " << gvars << std::endl;
    
    bad = false;
    
    // p nous indiquera la position de la chaîne URL.
    switch (t[0]) {
    case 'P': /* POST? */
	if (t.extract(1, 4) == "OST ") {
    	    p = t.to_charp(5);
	    post = true;
	} else {
//	    std::cerr << "Error: unknow request.\n";
	    bad = true;
	}
        Method = "POST";
	break;
    case 'G': /* GET? */
	if (t.extract(1, 3) == "ET ") {
	    p = t.to_charp(4);
	} else {
//	    std::cerr << "Error: unknow request.\n";
	    bad = true;
	}
        Method = "GET";
	break;
    default:
//	std::cerr << "Error: unknow request.\n";
	bad = true;
        Method = "Unknown";
    }
    
    if (!bad) {
	ssize_t poshttp, posslash;
        Uri = p;
	sppos = Uri.strrchr(' ');
	p = Uri.to_charp(0, sppos - 1);
	Uri = p;
	// On enlève tout le host spécifié éventuellement dans la requete.
	if ((poshttp = Uri.strstr("http://")) > 0) {
	    Uri = Uri.to_charp(poshttp + 7);
	    posslash = Uri.strchr('/');
	    // Certains navigateurs indiqueront uniquement http://host comme URL.
	    if (posslash >= 0) {
		host = Uri.extract(0, posslash - 1);
		Uri = Uri.to_charp(posslash);
	    } else {
		host = Uri;
		Uri = "";
	    }
	}
        Uri = UnMangle(Uri);
	posslash = Uri.strrchr('/');
	file = Uri.to_charp(posslash + 1);
	if (posslash > 0) {
	    domain = Uri.to_charp(0, posslash - 1);
	} else {
	    domain = "";
	}
    }
    return post;
}

/*
 * Ceci sert à rediriger le navigateur vers l'url de démarrage.
 */
void ProcessRequest::SendRedirect(Handle * s) {
    *s << "HTTP/1.1 301 Moved Permanently" << endhl << 
	 "Server: " << name << endhl <<
	 "Location: http://" << host << root << endhl <<
	 "Cache-Control: no-cache" << endhl <<
	 "Connection: closed" << endhl <<
	 "Content-Type: text/html" << endhl << endhl <<
         p->GetSkinner()->Redirect("http://" + host + root);
}

/*
 * Nous envoyons les entetes de réponse HTTP.
 */

void ProcessRequest::SendHeads(Handle * s, const String & mime, const String & extra, time_t lm) {
    time_t t = time(NULL);
    struct tm * ft = gmtime(&t);
    char buf[1025];
    strftime(buf, 1024, "%a, %d %b %Y %H:%M:%S GMT", ft);
    *s << "HTTP/1.1 200 OK" << endhl <<
	  "Date: " << buf << endhl <<
	  "Server: " << name << endhl;
    if (lm >=0) {
	ft = gmtime(&lm);
	strftime(buf, 1024, "%a, %d %b %Y %H:%M:%S GMT", ft);
    }
    *s << "Last-Modified: " << buf << endhl << extra <<
	  "Connection: closed" << endhl << 
	  "Content-Type: " << mime << endhl << endhl;
}

/*
 * Affichage d'une erreur 404.
 */

void ProcessRequest::ShowError(Handle * s) {
    *s << "HTTP/1.1 404 Not Found" << endhl <<
          "Server: " << name << endhl <<    
          "Cache-Control: no-cache" << endhl <<   
          "Connection: closed" << endhl <<      
          "Content-Type: text/html" << endhl << endhl <<
          p->GetSkinner()->Error("");
}

/*
 * Sert à déterminer le type mime à partir de l'extension du fichier.
 * Par défaut, nous mettons "text/plain".
 */

String ProcessRequest::GetMime(const String & f) {
    String ext;
    size_t ppos;
    
    ppos = f.strrchr('.');
    
    if (ppos >= 0) {
	ext = f.extract(ppos + 1);
	if (ext == "jpg") return "image/jpeg";
	if (ext == "jpeg") return "image/jpeg";
	if (ext == "htm") return "text/html";
	if (ext == "html") return "text/html";
	if (ext == "gif") return "image/gif";
	if (ext == "png") return "image/png";
	if (ext == "class") return "application/octet-stream";
    }
    
    return "text/plain";
}

String ProcessRequest::UnMangle(const String & s, int p) {
    String r;
    char c1, c2, c[2] = "x";
    
    if (s.strlen() <= p)
        return "";
    
    switch (s[p]) {
    case '%':
        c1 = s[p + 1];
        c2 = s[p + 2];
        
        if ((((c1 >= '0') && (c1 <= '9')) || ((c1 >= 'A') && (c1 <= 'F')) || ((c1 >= 'a') && (c1 <= 'f'))) &&
            (((c2 >= '0') && (c2 <= '9')) || ((c2 >= 'A') && (c2 <= 'F')) || ((c2 >= 'a') && (c2 <= 'f')))) {
            if ((c1 >= '0') && (c1 <= '9')) c1 -= '0';
            if ((c2 >= '0') && (c2 <= '9')) c2 -= '0';
            if ((c1 >= 'A') && (c1 <= 'F')) c1 -= 'A' - 10;
            if ((c2 >= 'A') && (c2 <= 'F')) c2 -= 'A' - 10;
            if ((c1 >= 'a') && (c1 <= 'f')) c1 -= 'a' - 10;
            if ((c2 >= 'a') && (c2 <= 'f')) c2 -= 'a' - 10;
            c[0] = c1 * 16 + c2;
            r = c;
            p += 3;
        } else {
            r = "%";
            p++;
        }
        break;
    case '+':
        r = " ";
        p++;
        break;
    default:
        r = s[p];
        p++;
        break;
    }
    
    return r + UnMangle(s, p);
}

HttpServ::HttpServ(Action * ap, int port, const String & nname) throw (GeneralException) : root("/bin/start") {
    bool r = true;
    
    p = ap;
    name = nname;
    localport = port;
    
//  std::cerr << "Initialising Mini HTTP-Server on port " << localport << std::endl;
    
    r = Listener.SetLocal("", port);
    if (!r) {
	throw GeneralException(_("Initialisation of the Mini HTTP-Server failed: can't bind"));
    }
    
    r = Listener.Listen();
    
    if (!r) {
	throw GeneralException(_("Initialisation of the Mini HTTP-Server failed: can't listen"));
    }
    
    Listener.SetNonBlock();
    WaitFor(&Listener, W4_STICKY | W4_READING);
    
//  std::cerr << "Mini HTTP-Server '" << name << "' ready and listening for port " << port << std::endl;
}

HttpServ::~HttpServ(void) {
    Listener.close();
}

void HttpServ::SetRoot(const String & _root) {
    root = _root;
}

int HttpServ::Do() throw (GeneralException) {
    try {
	Socket s = Listener.Accept();
	s.SetNonBlock();
	new ProcessRequest(p, s, name, localport, root);
    }
    catch (GeneralException) {
    }
    return TASK_ON_HOLD;
}

String HttpServ::GetName() {
    return String("Mini HTTP-Server '") + name + "'";
}

class BuildHttpResponse : public Task {
  public:
      BuildHttpResponse(HttpResponse * _hr, Handle * _out) : hr(_hr), out(_out) { SetBurst(); }
      virtual ~BuildHttpResponse() { }
    virtual String GetName() { return "BuildHttpResponse"; }
    virtual int Do() throw (GeneralException) {
        Buffer * b;
        
        switch (current) {
        case 0:
            if (hr->Prepared()) {
                b = &hr->contents;
                current = 2;
            } else {
                b = new Buffer();
                hr->PrepareResponse(b);
                current = 1;
            }

            t = new CopyJob(b, out, -1, b != &hr->contents);
            WaitFor(t);
            Suspend(TASK_ON_HOLD);
        
        case 1:
            delete t;
            t = new CopyJob(&hr->contents, out);
            WaitFor(t);
            current = 2;
            Suspend(TASK_ON_HOLD);
            
        case 2:
            delete t;
        }

        return TASK_DONE;
    }
  private:
    HttpResponse * hr;
    Handle * out;
    Task * t;
};

HttpResponse::HttpResponse() : mime_type("text/html; charset=iso8859-1"), location(""), server_name("GruiK Server v0.2"), return_code(HTTP_200_OK), last_modified(time(NULL)), cache(true), already_prepared(false), builder(0) {
}

HttpResponse::~HttpResponse() {
}

Task * HttpResponse::BuildResponse(Handle * out) {
    ChainTasks::tasklist_t l;
    Task * t;
    
    t = new BuildHttpResponse(this, out);

    if (builder) {
        l.push_back(builder);
        l.push_back(t);
        t = new ChainTasks(l);
    }
    
    return t;
}

void HttpResponse::PrepareResponse(Handle * b) {
    if (already_prepared)
        return;
    
    if (!b)
        b = &contents;
    
    already_prepared = true;

    char buf[1025];

    time_t cur_time = time(NULL);
    struct tm * ft = gmtime(&cur_time);

    strftime(buf, 1024, "%a, %d %b %Y %H:%M:%S GMT", ft);
    
    (*b) << "HTTP/1.1 " << return_code << " " << code_to_string() << "\r\n"
         << "Server: " << server_name << "\r\n"
         << "Date: " << buf << "\r\n";
         
    if (!cache)
        (*b) << "Cache-Control: no-cache\r\n";
         
    (*b) << "Connection: closed\r\n"
         << "Content-Type: " << mime_type << "\r\n";
    
    
    if (location != "") {
        switch (return_code) {
        case HTTP_301_PERM_MOVED:
        case HTTP_302_FOUND:
            (*b) << "Location: " << location << "\r\n";
            break;
        case HTTP_401_UNAUTHORIZED:
            if (domain != "") {
                SHA1 h;
                String digest;
                
                h.Update(location + ":" + ((Uint64) time(0)) + ":" + domain + ":" + rand());
                digest = h.Finish();
                
                (*b) << "WWW-Authenticate: Digest realm=\"" << location << "\", domain=\"" << domain << "\", nonce=\"" << digest << "\", algorithm=\"MD5\", qop=\"auth\"\r\n";
            } else {
                (*b) << "WWW-Authenticate: Basic realm=\"" << location << "\"\r\n";
            }
            break;
        }
    }
    if (last_modified >= 0) {
	ft = gmtime(&last_modified);
	strftime(buf, 1024, "%a, %d %b %Y %H:%M:%S GMT", ft);
        (*b) << "Last-Modified: " << buf << "\r\n";
    }
    
    (*b) << "\r\n";
}

bool HttpResponse::Prepared() {
    return already_prepared;
}

String HttpResponse::code_to_string() {
    switch (return_code) {
    case HTTP_200_OK:
        return "OK";
    case HTTP_301_PERM_MOVED:
        return "Moved Permanently";
    case HTTP_302_FOUND:
        return "Found";
    case HTTP_400_BAD_REQUEST:
        return "Bad Request";
    case HTTP_401_UNAUTHORIZED:
        return "Authorization Required";
    case HTTP_403_FORBIDDEN:
        return "Forbidden";
    case HTTP_404_NOT_FOUND:
        return "Not Found";
    case HTTP_500_INTERNAL_ERROR:
        return "Internal Error";
    case HTTP_503_SERVICE_UNAVAILABLE:
        return "Service Unavailable";
    }
}