ref: a411870ee4640241e3c494367d922847da84f972
dir: /appl/cmd/webgrab.b/
# Webgrab -- for getting html pages and the subordinate files (images, frame children)
# they refer to (using "src=..." in a tag) into the local file space.
# Assume http: scheme if none specified.
# Usage:
# webgrab [-r] [-v] [-o stem] url
# If stem is specified, file will be saved in stem.html and images will
# go in stem_1.jpg (or .gif, ...), stem_2.jpg, etc.
# If stem is not specified, derive it from url (see getstem comment, below).
# If -r is specified, get "raw", i.e., no image fetching/html munging.
# If -v is specified (verbose), print some progress information,
# with more if -vv is given.
implement Webgrab;
include "sys.m";
sys: Sys;
FD: import sys;
include "draw.m";
include "string.m";
S: String;
include "url.m";
U: Url;
ParsedUrl: import U;
include "daytime.m";
DT: Daytime;
include "bufio.m";
B: Bufio;
include "dial.m";
D: Dial;
include "arg.m";
Webgrab: module
{
init: fn(ctxt: ref Draw->Context, args: list of string);
};
stderr: ref FD;
verbose := 0;
postbody : string;
httpproxy: ref Url->ParsedUrl;
noproxydoms: list of string; # domains that don't require proxy
init(nil: ref Draw->Context, args: list of string)
{
sys = load Sys Sys->PATH;
stderr = sys->fildes(2);
S = load String String->PATH;
U = load Url Url->PATH;
DT = load Daytime Daytime->PATH;
D = load Dial Dial->PATH;
B = load Bufio Bufio->PATH;
arg := load Arg Arg->PATH;
if(S == nil || U == nil || DT == nil || B == nil || arg == nil)
error_exit("can't load a module");
U->init();
stem := "";
rawflag := 0;
arg->init(args);
arg->setusage("webgrab [-r] [-v[v]] [-p postbody] [-o stem] url");
url := "";
while((o := arg->opt()) != 0)
case o {
'r' =>
rawflag = 1;
'v' =>
verbose++;
'o' =>
stem = arg->earg();
'p' =>
postbody = arg->earg();
* =>
arg->usage();
}
args = arg->argv();
if(len args != 1)
arg->usage();
url = hd args;
arg = nil;
(nil,xr) := S->splitstrl(url,"//");
(nil,yr) := S->splitl(url,":");
if(xr == "" && yr == "")
url = "http://" + url;
u := U->makeurl(url);
if(stem == "")
stem = getstem(u);
readconfig();
grab(u, stem, rawflag);
}
readconfig()
{
cfgio := B->open("/services/webget/config", sys->OREAD);
if(cfgio != nil) {
for(;;) {
line := B->cfgio.gets('\n');
if(line == "") {
B->cfgio.close();
break;
}
if(line[0]=='#')
continue;
(key, val) := S->splitl(line, " \t=");
val = S->take(S->drop(val, " \t="), "^\r\n");
if(val == "")
continue;
case key {
"httpproxy" =>
if(val == "none")
continue;
# val should be host or host:port
httpproxy = U->makeurl("http://" + val);
if(verbose)
sys->fprint(stderr, "Using http proxy %s\n", httpproxy.tostring());
"noproxy" or
"noproxydoms" =>
(nil, noproxydoms) = sys->tokenize(val, ";, \t");
}
}
}
}
# Make up a stem for forming save-file-names, based on url u.
# Use the last non-nil component of u.path, without a final extension,
# else use the host. Then, if the stem still contains a '.' (e.g., www.lucent)
# use the part after the final '.'.
# Finally, if all else fails, use use "grabout".
getstem(u: ref ParsedUrl) : string
{
stem := "";
if(u.path != "") {
(l, r) := S->splitr(u.path, "/");
if(r == "") {
# path ended with '/'; try next to last component
if(l != "")
(l, r) = S->splitr(l[0:len l - 1], "/");
}
if(r != "")
stem = r;
}
if(stem == "")
stem = u.host;
if(stem != "") {
ext: string;
(stem, ext) = S->splitr(stem, ".");
if(stem == "")
stem = ext;
else
stem = stem[0:len stem - 1];
(nil, stem) = S->splitr(stem, ".");
}
if(stem == "")
stem = "grabout";
return stem;
}
grab(u: ref ParsedUrl, stem: string, rawflag: int)
{
(err, contents, fd, actual) := httpget(u);
if(err != "")
error_exit(err);
ish := is_html(contents);
if(ish)
contents = addfetchcomment(contents, u, actual);
if(rawflag || !ish) {
writebytes(stem, contents, fd);
return;
}
# get subordinates, modify contents
subs : list of (string, string);
(contents, subs) = subfix(contents, stem);
writebytes(stem + ".html", contents, fd);
for(l := subs; l != nil; l = tl l) {
(fname, suburl) := hd l;
subu := U->makeurl(suburl);
subu.makeabsolute(actual);
(suberr, subcontents, subfd, nil) := httpget(subu);
if(suberr != "") {
sys->fprint(stderr, "webgrab: can't fetch subordinate %s from %s: %s\n", fname, subu.tostring(), suberr);
continue;
}
writebytes(fname, subcontents, subfd);
}
}
# Fix the html in array a so that referenced subordinate files (SRC= or BACKGROUND= fields of tags)
# are replaced with local names (stem_1.xxx, stem_2.xxx, etc.),
# and return the fixed array along with a list of (local name, subordinate url)
# of images to be fetched.
subfix(a: array of byte, stem: string) : (array of byte, list of (string, string))
{
alen := len a;
if(alen == 0)
return (a, nil);
nsubs := 0;
newa := array[alen + 1000] of byte;
newai := 0;
j := 0;
intag := 0;
incom := 0;
quote := 0;
subs : list of (string, string) = nil;
for(i := 0; i < alen; i++) {
c := int a[i];
if(incom) {
if(amatch(a, i, alen, "-->")) {
incom = 0;
i = i+2;
}
}
else if(intag) {
if(quote==0 && (amatch(a, i, alen, "src") || amatch(a, i, alen, "background"))) {
v := "";
eqi := 0;
if(amatch(a, i, alen, "src"))
k := i+3;
else
k = i+10;
for(; k < alen; k++)
if(!iswhite(int a[k]))
break;
if(k < alen && int a[k] == '=') {
eqi = k;
k++;
while(k<alen && iswhite(int a[k]))
k++;
if(k<alen) {
kstart := k;
c = int a[k];
if(c == '\'' || c== '"') {
quote = int a[k++];
while(k<alen && (int a[k])!=quote)
k++;
v = string a[kstart+1:k];
k++;
}
else {
while(k<alen && !iswhite(int a[k]) && int a[k] != '>')
k++;
v = string a[kstart:k];
}
}
}
if(v != "") {
f := "";
for(l := subs; l != nil; l = tl l) {
(ff,uu) := hd l;
if(v == uu) {
f = ff;
break;
}
}
if(f == "") {
nsubs++;
f = stem + "_" + string nsubs + getsuff(v);
subs = (f, v) :: subs;
}
# should check for newa too small
newa[newai:] = a[j:eqi+1];
newai += eqi+1-j;
xa := array of byte f;
newa[newai:] = xa;
newai += len xa;
j = k;
}
i = k-1;
}
if(c == '>' && quote == 0)
intag = 0;
if(quote) {
if(quote == c)
quote = 0;
else if(c == '"' || c == '\'')
quote = c;
}
}
else if(c == '<')
intag = 1;
}
if(nsubs == 0)
return (a, nil);
if(i > j) {
newa[newai:] = a[j:i];
newai += i-j;
}
ans := array[newai] of byte;
ans[0:] = newa[0:newai];
anssubs : list of (string, string) = nil;
for(ll := subs; ll != nil; ll = tl ll)
anssubs = hd ll :: anssubs;
return (ans, anssubs);
}
# add c after all f's in a
fixnames(a: array of byte, f: string, c: byte)
{
alen := len a;
n := alen - len f;
for(i := 0; i < n; i++) {
if(amatch(a, i, alen, f)) {
a[i+len f] = c;
}
}
}
amatch(a: array of byte, i, alen: int, s: string) : int
{
slen := len s;
for(k := 0; i+k < alen && k < slen; k++) {
c := int a[i+k];
if(c >= 'A' && c <= 'Z')
c = c + (int 'a' - int 'A');
if(c != s[k])
break;
}
if(k == slen) {
return 1;
}
return 0;
}
getsuff(ustr: string) : string
{
u := U->makeurl(ustr);
if(u.path != "") {
for(i := len u.path - 1; i >= 0; i--) {
c := u.path[i];
if(c == '.')
return u.path[i:];
if(c == '/')
break;
}
}
return "";
}
iswhite(c: int) : int
{
return (c==' ' || c=='\t' || c=='\n' || c=='\r');
}
# Add a comment to end of a giving date and source of fetch
addfetchcomment(a: array of byte, u, actu: ref ParsedUrl) : array of byte
{
now := DT->text(DT->local(DT->now()));
ustr := u.tostring();
actustr := actu.tostring();
comment := "\n<!-- Fetched " + now + " from " + ustr;
if(ustr != actustr)
comment += ", redirected to " + actustr;
comment += " -->\n";
acom := array of byte comment;
newa := array[len a + len acom] of byte;
newa[0:] = a;
newa[len a:] = acom;
return newa;
}
# Get u, return (error string, body, actual url of source, after redirection)
httpget(u: ref ParsedUrl) : (string, array of byte, ref Sys->FD, ref ParsedUrl)
{
ans, body : array of byte;
restfd: ref Sys->FD;
req : string;
for(redir := 0; redir < 10; redir++) {
if(u.port == "")
u.port = "80"; # default IP port for HTTP
if(verbose)
sys->fprint(stderr, "connecting to %s\n", u.host);
dialhost, port: string;
if(httpproxy != nil && need_proxy(u.host)) {
dialhost = httpproxy.host;
port = httpproxy.port;
}
else {
dialhost = u.host;
port = u.port;
}
dest := D->netmkaddr(dialhost, "tcp", port);
net := D->dial(dest, nil);
if(net == nil)
return (sys->sprint("can't dial %s: %r", dest), nil, nil, nil);
# prepare request
if(u.query != ""){
u.query = "?" + u.query;
}
if (postbody == nil){
if(httpproxy == nil || !need_proxy(u.host)){
req = sys->sprint("GET /%s%s HTTP/1.0\r\n"+
"Host: %s\r\n"+
"User-agent: Inferno/webgrab\r\n"+
"Cache-Control: no-cache\r\n"+
"Pragma: no-cache\r\n\r\n",
u.path, u.query, u.host);
}else{
req = sys->sprint("GET http:///%s%s HTTP/1.0\r\n"+
"Host: %s\r\n"+
"User-agent: Inferno/webgrab\r\n"+
"Cache-Control: no-cache\r\n"+
"Pragma: no-cache\r\n\r\n",
u.host, u.path, u.host);
}
}else{
req = sys->sprint("POST /%s HTTP/1.0\r\n"+
"Host: %s\r\n"+
"Content-type: application/x-www-form-urlencoded\r\n"+
"Content-length: %d\r\n"+
"User-agent: Inferno/webgrab\r\n"+
"\r\n"+"%s",
u.path, u.host, len postbody, postbody);
}
if(verbose)
sys->fprint(stderr, "writing request: %s\n", req);
areq := array of byte req;
n := sys->write(net.dfd, areq, len areq);
if(n != len areq)
return (sys->sprint("write problem: %r"), nil, nil, nil);
(ans, restfd) = readbytes(net.dfd);
(status, rest) := stripline(ans);
if(verbose)
sys->fprint(stderr, "response: %s\n", status);
(vers, statusrest) := S->splitl(status, " ");
if(!S->prefix("HTTP/", vers))
return ("bad reply status: " + status, rest, restfd, nil);
code := int statusrest;
location := "";
body = rest;
for(;;) {
hline: string;
(hline, body) = stripline(body);
if(hline == "")
break;
if(verbose > 1)
sys->fprint(stderr, "%s\n", hline);
if(!iswhite(hline[0])) {
(hname, hrest) := S->splitl(hline, ":");
if(hrest != "") {
hname = S->tolower(hname);
hval := S->drop(hrest, ": \t");
hval = S->take(hval, "^ \t");
if(hname == "location")
location = hval;
}
}
}
if(code != 200) {
if((code == 300 || code == 301 || code == 302) && location != "") {
# MultipleChoices, MovedPerm, or MovedTemp
if(verbose)
sys->fprint(stderr, "redirect to %s\n", location);
u = U->makeurl(location);
continue;
}
return ("status not ok: " + status, rest, restfd, u);
}
break;
}
return ("", body, restfd, u);
}
need_proxy(h: string) : int
{
doml := noproxydoms;
if(doml == nil)
return 1; # all domains need proxy
lh := len h;
for(dom := hd doml; doml != nil; doml = tl doml) {
ld := len dom;
if(lh >= ld && h[lh-ld:] == dom)
return 0; # domain is on the noproxy list
}
return 1;
}
# Simple guess test for HTML: first non-white byte is '<'
is_html(a: array of byte) : int
{
for(i := 0; i < len a; i++)
if(!iswhite(int a[i]))
break;
if(i < len a && a[i] == byte '<')
return 1;
return 0;
}
readbytes(fd: ref Sys->FD) : (array of byte, ref Sys->FD)
{
buf := array[Sys->ATOMICIO] of byte;
i := 0;
avail := len buf;
while (avail > 0) {
n := sys->read(fd, buf[i:], avail);
if(n <= 0) {
fd = nil;
break;
}
i += n;
avail -= n;
}
return (buf[0:i], fd);
}
writebytes(f: string, a: array of byte, fd: ref Sys->FD)
{
ofd: ref Sys->FD;
if (f == "-")
ofd = sys->fildes(1);
else
ofd = sys->create(f, Sys->OWRITE, 8r666);
if(ofd == nil) {
sys->fprint(stderr, "webgrab: can't create %s: %r\n", f);
return;
}
i := 0;
clen := len a;
while(i < clen) {
n := sys->write(ofd, a[i:], clen-i);
if(n < 0) {
sys->fprint(stderr, "webgrab: write error: %r\n");
return;
}
i += n;
}
if(fd != nil) {
buf := array[Sys->ATOMICIO] of byte;
while((n := sys->read(fd, buf, len buf)) > 0) {
if(sys->write(ofd, buf, n) != n) {
sys->fprint(stderr, "webgrab: write error: %r\n");
return;
}
}
if(n < 0) {
sys->fprint(stderr, "webgrab: read error: %r\n");
return;
}
clen += n;
}
if (f != "-")
sys->fprint(stderr, "created %s, %d bytes\n", f, clen);
}
stripline(b: array of byte) : (string, array of byte)
{
n := len b - 1;
for(i := 0; i < n; i++)
if(b[i] == byte '\r' && b[i+1] == byte '\n')
return (string b[0:i], b[i+2:]);
return ("", b);
}
error_exit(msg: string)
{
sys->fprint(sys->fildes(2), "%s\n", msg);
raise "fail:error";
}