ftpAPI.py :  » Network » Grail-Internet-Browser » grail-0.6 » protocols » Python Open Source

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Python Open Source » Network » Grail Internet Browser 
Grail Internet Browser » grail 0.6 » protocols » ftpAPI.py
"""FTP interface using the new protocol API.

XXX Main deficiencies:

- poll*() always returns ready
- should read the headers more carefully (no blocking)
- (could even *write* the headers more carefully)
- should poll the connection making part too
- no GC of ftp cache entries
- should reuse ftp cache entries for same server by using cdup/cd
- if a file retrieval returns error 550 it is retried as directory listing

"""


import string
import regex
import regsub

import ftplib
from urllib import unquote,splithost,splitport,splituser,\
     splitpasswd, splitattr, splitvalue, quote
from urlparse import urljoin
import mimetools
from Assert import Assert
import grailutil
import socket

app = grailutil.get_grailapp()          # app.guess_type(url)


# Stages
META = 'META'
DATA = 'DATA'
EOF = 'EOF'
DONE = 'DONE'


LISTING_HEADER = """<HTML>
<HEAD><TITLE>FTP Directory: %(url)s</TITLE></HEAD>
<BODY>
<H1>FTP Directory: %(url)s</H1>
<PRE>"""

LISTING_TRAILER = """</PRE>
</BODY>
"""

# pattern catches file names with embedded spaces and correctly chops
# off symbolic links.  assumption is anything after `yyyy' or `hh:mm'
# field and before optional `-> symlink' field is the name of the file
LISTING_PATTERN = (
    "^\("                               # group 1
        "[-a-z]"                        # file type
        "[-a-z][-a-z][-a-z]"            # owner rwx
        "[-a-z][-a-z][-a-z]"            # group rwx
        "[-a-z][-a-z][-a-z]"            # world rwx
    "\)"                                # end group 1
    "\("                                # group 2
        "[ \t]+.*[ \t]+"                # links, owner, grp, sz, mnth, day
        "[0-9][0-9]:?[0-9][0-9]"        # year or hh:mm
        "[ \t]+"                        # spaces
    "\)"                                # end group 2
    "\("                                # group 3
        "\([^-]\|-[^>]\)+"              # lots of chars, but not symlink
    "\)"                                # end group 3
    "\("                                # optional group 5
        "[ \t]+->.*"                    # spaces followed by symlink 
    "\)?"                               # end optional group 5
    "$"                                 # end of string
    )


ftpcache = {}                           # XXX Ouch!  A global!


class ftp_access:

    def __init__(self, url, method, params):
        Assert(method == 'GET')
        netloc, path = splithost(url)
        if not netloc: raise IOError, ('ftp error', 'no host given')
        host, port = splitport(netloc)
        user, host = splituser(host)
        if user: user, passwd = splitpasswd(user)
        else: passwd = None
        host = socket.gethostbyname(host)
        if port:
            try:
                port = string.atoi(port)
            except string.atoi_error:
                raise IOError, ('ftp error', 'bad port')
        else:
            port = ftplib.FTP_PORT
        path, attrs = splitattr(path)
        self.url = "ftp://%s%s" % (netloc, path)
        dirs = string.splitfields(path, '/')
        dirs, file = dirs[:-1], dirs[-1]
        self.content_length = None
        if not file:
            self.content_type, self.content_encoding = None, None
            type = 'd'
        else:
            self.content_type, self.content_encoding = app.guess_type(file)
            if self.content_encoding:
                type = 'i'
            elif self.content_type and self.content_type[:5] == 'text/':
                type = 'a'
            elif file[-1] == '/':
                type = 'd'
            else:
                type = 'i'
        if dirs and not dirs[0]: dirs = dirs[1:]
        key = (user, host, port, string.joinfields(dirs, '/'))
        self.debuglevel = None
        try:
            if not ftpcache.has_key(key):
                ftpcache[key] = []
            for attr in attrs:
                [attr, value] = map(string.lower, splitvalue(attr))
                if attr == 'type' and value in ('a', 'i', 'd'):
                    type = value
                elif attr == 'debug':
                    try:
                        self.debuglevel = string.atoi(value)
                    except string.atoi_error:
                        pass
            candidates = ftpcache[key]
            for cand in candidates:
                if not cand.busy():
                    break
            else:
                cand = ftpwrapper(user, passwd,
                                  host, port, dirs, self.debuglevel)
                candidates.append(cand)
            # XXX Ought to clean the cache every once in a while
            self.cand = cand
            self.sock, self.isdir = cand.retrfile(file, type)
            self.content_length = cand.content_length
        except ftplib.all_errors, msg:
            raise IOError, ('ftp error', msg)
        self.state = META

    def pollmeta(self):
        Assert(self.state == META)
        return "Ready", 1

    def getmeta(self):
        Assert(self.state == META)
        self.state = DATA
        headers = {}
        if self.isdir:
            if self.url and self.url[-1:] != '/':
                self.url = self.url + '/'
            self.content_type = 'text/html'
            self.content_encoding = None
        if self.content_type:
            headers['content-type'] = self.content_type
        if self.content_encoding:
            headers['content-encoding'] = self.content_encoding
        if self.content_length:
            headers['content-length'] = `self.content_length`
        self.lines = []                 # Only used of self.isdir
        return 200, "OK", headers

    def polldata(self):
        Assert(self.state in (EOF, DATA))
        return "Ready", 1

    def getdata(self, maxbytes):
        if self.state == EOF:
            self.state = DONE
            return ""
        Assert(self.state == DATA)
        data = self.sock.recv(maxbytes)
        if self.debuglevel > 4: print "*data*", `data`
        if not data:
            self.state = DONE
        if self.isdir:
            self.addlistingdata(data)
            data = self.getlistingdata()
            if self.state == DONE and data:
                self.state = EOF        # Allow one more call
        return data

    def addlistingdata(self, data):
        if not data:
            if self.lines:
                while self.lines and self.lines[-1] == "":
                    del self.lines[-1]
                self.lines.append(None) # Mark the end
        else:
            lines = string.splitfields(data, '\n')
            if self.debuglevel > 3:
                for line in lines: print "*addl*", `line`
            if self.lines:
                lines[0] = self.lines[-1] + lines[0]
                self.lines[-1:] = lines
            else:
                lines.insert(0, None)   # Mark the start
                self.lines = lines

    def getlistingdata(self):
        if not self.lines:
            return ""
        lines, self.lines = self.lines[:-1], self.lines[-1:]
        data = ""
        prog = regex.compile(self.listing_pattern)
        for line in lines:
            if self.debuglevel > 2:
                print "*getl*", `line`
            if line is None:
                data = data + self.listing_header % {'url':
                                                     self.escape(self.url)}
                continue
            if line[-1:] == '\r': line = line[:-1]
            if prog.match(line) < 0:
                line = self.escape(line) + '\n'
                data = data + line
                continue
            mode, middle, name, symlink = prog.group(1, 2, 3, 5)
            rawname = name
            [mode, middle, name] = map(self.escape, [mode, middle, name])
            href = urljoin(self.url, quote(rawname))
            if len(mode) == 10 and mode[0] == 'd' or name[-1:] == '/':
                if name[-1:] != '/':
                    name = name + '/'
                if href[-1:] != '/':
                    href = href + '/'
            line = '%s%s<A HREF="%s">%s</A>%s\n' % (
                mode, middle, self.escape(href), name,
                (symlink and symlink or ''))
            data = data + line
        if self.lines == [None]:
            data = data + self.listing_trailer
            self.lines = []
        return data

    listing_header = LISTING_HEADER
    listing_trailer = LISTING_TRAILER
    listing_pattern = LISTING_PATTERN

    def escape(self, s):
        if not s: return ""
        s = regsub.gsub('&', '&amp;', s) # Must be done first
        s = regsub.gsub('<', '&lt;', s)
        s = regsub.gsub('>', '&gt;', s)
        return s

    def fileno(self):
        return self.sock.fileno()

    def close(self):
        sock = self.sock
        cand = self.cand
        self.sock = None
        self.cand = None
        if sock:
            sock.close()
        if cand:
            cand.done()


class ftpwrapper:

    """Helper class for cache of open FTP connections"""

    def __init__(self, user, passwd, host, port, dirs, debuglevel=None):
        self.user = unquote(user or '')
        self.passwd = unquote(passwd or '')
        self.host = host
        self.port = port
        self.dirs = []
        self.content_length = None
        for dir in dirs:
            self.dirs.append(unquote(dir))
        self.debuglevel = debuglevel
        self.reset()

    def __del__(self):
        self.done()
        self.ftp.quit()

    def reset(self):
        self.conn = None
        self.ftp = GrailFTP()
        if self.debuglevel is not None:
            self.ftp.set_debuglevel(self.debuglevel)
        self.ftp.connect(self.host, self.port)
        self.ftp.login(self.user, self.passwd)
        for dir in self.dirs:
            self.ftp.cwd(dir)

    def busy(self):
        return self.conn and 1

    def done(self):
        conn = self.conn
        self.conn = None
        if conn:
            conn.close()
            try:
                self.ftp.voidresp()
            except ftplib.all_errors:
                print "[ftp.voidresp() failed]"

    def retrfile(self, file, type):
        if type == 'd': cmd = 'TYPE A'; isdir = 1
        else: cmd = 'TYPE ' + string.upper(type); isdir = 0
        try:
            self.ftp.voidcmd(cmd)
        except ftplib.all_errors:
            self.reset()
            self.ftp.voidcmd(cmd)
        conn = None
        if file and not isdir:
            try:
                cmd = 'RETR ' + unquote(file)
                conn = self.ftp.transfercmd(cmd)
            except ftplib.error_perm, reason:
                if reason[:3] != '550':
                    raise IOError, ('ftp error', reason)
            else:
                self.content_length = self.ftp._xfer_size
        if not conn:
            # Try a directory listing
            isdir = 1
            if file: cmd = 'LIST ' + file
            else: cmd = 'LIST'
            conn = self.ftp.transfercmd(cmd)
        self.conn = conn
        return conn, isdir


class GrailFTP(ftplib.FTP):
    #
    #  Hackish subclass of ftplib.FTP to allow the transfer size to be
    #  available for the creation of a content-length header.
    #
    import regex
    _size_re = regex.compile("(\([0-9][0-9]*\) bytes)", regex.casefold)

    _xfer_size = None

    def getresp(self):
        resp = ftplib.FTP.getresp(self)
        if len(resp) >= 3 and resp[:3] == "150" \
           and self._size_re.search(resp) >= 0:
                self._xfer_size = string.atoi(self._size_re.group(1))
        return resp


# To test this, use ProtocolAPI.test()
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