retr.c

一个从网络上自动下载文件的自由工具

        }
    }

  if (proxy_url)
    {
      url_free (proxy_url);
      proxy_url = NULL;
    }

  location_changed = (result == NEWLOCATION);
  if (location_changed)
    {
      char *construced_newloc;
      struct url *newloc_parsed;

      assert (mynewloc != NULL);

      if (local_file)
        xfree (local_file);

      /* The HTTP specs only allow absolute URLs to appear in
         redirects, but a ton of boneheaded webservers and CGIs out
         there break the rules and use relative URLs, and popular
         browsers are lenient about this, so wget should be too. */
      construced_newloc = uri_merge (url, mynewloc);
      xfree (mynewloc);
      mynewloc = construced_newloc;

      /* Now, see if this new location makes sense. */
      newloc_parsed = url_parse (mynewloc, &up_error_code);
      if (!newloc_parsed)
        {
          logprintf (LOG_NOTQUIET, "%s: %s.\n", escnonprint_uri (mynewloc),
                     url_error (up_error_code));
          url_free (u);
          xfree (url);
          xfree (mynewloc);
          RESTORE_POST_DATA;
          return result;
        }

      /* Now mynewloc will become newloc_parsed->url, because if the
         Location contained relative paths like .././something, we
         don't want that propagating as url.  */
      xfree (mynewloc);
      mynewloc = xstrdup (newloc_parsed->url);

      /* Check for max. number of redirections.  */
      if (++redirection_count > opt.max_redirect)
        {
          logprintf (LOG_NOTQUIET, _("%d redirections exceeded.\n"),
                     opt.max_redirect);
          url_free (newloc_parsed);
          url_free (u);
          xfree (url);
          xfree (mynewloc);
          RESTORE_POST_DATA;
          return WRONGCODE;
        }

      xfree (url);
      url = mynewloc;
      url_free (u);
      u = newloc_parsed;

      /* If we're being redirected from POST, we don't want to POST
         again.  Many requests answer POST with a redirection to an
         index page; that redirection is clearly a GET.  We "suspend"
         POST data for the duration of the redirections, and restore
         it when we're done. */
      if (!post_data_suspended)
        SUSPEND_POST_DATA;

      goto redirected;
    }

  if (local_file)
    {
      if (*dt & RETROKF)
        {
          register_download (u->url, local_file);
          if (redirection_count && 0 != strcmp (origurl, u->url))
            register_redirection (origurl, u->url);
          if (*dt & TEXTHTML)
            register_html (u->url, local_file);
        }
    }

  if (file)
    *file = local_file ? local_file : NULL;
  else
    xfree_null (local_file);

  url_free (u);

  if (redirection_count)
    {
      if (newloc)
        *newloc = url;
      else
        xfree (url);
    }
  else
    {
      if (newloc)
        *newloc = NULL;
      xfree (url);
    }

  RESTORE_POST_DATA;

  return result;
}

/* Find the URLs in the file and call retrieve_url() for each of them.
   If HTML is true, treat the file as HTML, and construct the URLs
   accordingly.

   If opt.recursive is set, call retrieve_tree() for each file.  */

uerr_t
retrieve_from_file (const char *file, bool html, int *count)
{
  uerr_t status;
  struct urlpos *url_list, *cur_url;

  url_list = (html ? get_urls_html (file, NULL, NULL)
              : get_urls_file (file));
  status = RETROK;             /* Suppose everything is OK.  */
  *count = 0;                  /* Reset the URL count.  */

  for (cur_url = url_list; cur_url; cur_url = cur_url->next, ++*count)
    {
      char *filename = NULL, *new_file = NULL;
      int dt;

      if (cur_url->ignore_when_downloading)
        continue;

      if (opt.quota && total_downloaded_bytes > opt.quota)
        {
          status = QUOTEXC;
          break;
        }
      if ((opt.recursive || opt.page_requisites)
          && (cur_url->url->scheme != SCHEME_FTP || getproxy (cur_url->url)))
        {
          int old_follow_ftp = opt.follow_ftp;

          /* Turn opt.follow_ftp on in case of recursive FTP retrieval */
          if (cur_url->url->scheme == SCHEME_FTP) 
            opt.follow_ftp = 1;
          
          status = retrieve_tree (cur_url->url->url);

          opt.follow_ftp = old_follow_ftp;
        }
      else
        status = retrieve_url (cur_url->url->url, &filename, &new_file, NULL, &dt, opt.recursive);

      if (filename && opt.delete_after && file_exists_p (filename))
        {
          DEBUGP (("\
Removing file due to --delete-after in retrieve_from_file():\n"));
          logprintf (LOG_VERBOSE, _("Removing %s.\n"), filename);
          if (unlink (filename))
            logprintf (LOG_NOTQUIET, "unlink: %s\n", strerror (errno));
          dt &= ~RETROKF;
        }

      xfree_null (new_file);
      xfree_null (filename);
    }

  /* Free the linked list of URL-s.  */
  free_urlpos (url_list);

  return status;
}

/* Print `giving up', or `retrying', depending on the impending
   action.  N1 and N2 are the attempt number and the attempt limit.  */
void
printwhat (int n1, int n2)
{
  logputs (LOG_VERBOSE, (n1 == n2) ? _("Giving up.\n\n") : _("Retrying.\n\n"));
}

/* If opt.wait or opt.waitretry are specified, and if certain
   conditions are met, sleep the appropriate number of seconds.  See
   the documentation of --wait and --waitretry for more information.

   COUNT is the count of current retrieval, beginning with 1. */

void
sleep_between_retrievals (int count)
{
  static bool first_retrieval = true;

  if (first_retrieval)
    {
      /* Don't sleep before the very first retrieval. */
      first_retrieval = false;
      return;
    }

  if (opt.waitretry && count > 1)
    {
      /* If opt.waitretry is specified and this is a retry, wait for
         COUNT-1 number of seconds, or for opt.waitretry seconds.  */
      if (count <= opt.waitretry)
        xsleep (count - 1);
      else
        xsleep (opt.waitretry);
    }
  else if (opt.wait)
    {
      if (!opt.random_wait || count > 1)
        /* If random-wait is not specified, or if we are sleeping
           between retries of the same download, sleep the fixed
           interval.  */
        xsleep (opt.wait);
      else
        {
          /* Sleep a random amount of time averaging in opt.wait
             seconds.  The sleeping amount ranges from 0.5*opt.wait to
             1.5*opt.wait.  */
          double waitsecs = (0.5 + random_float ()) * opt.wait;
          DEBUGP (("sleep_between_retrievals: avg=%f,sleep=%f\n",
                   opt.wait, waitsecs));
          xsleep (waitsecs);
        }
    }
}

/* Free the linked list of urlpos.  */
void
free_urlpos (struct urlpos *l)
{
  while (l)
    {
      struct urlpos *next = l->next;
      if (l->url)
        url_free (l->url);
      xfree_null (l->local_name);
      xfree (l);
      l = next;
    }
}

/* Rotate FNAME opt.backups times */
void
rotate_backups(const char *fname)
{
  int maxlen = strlen (fname) + 1 + numdigit (opt.backups) + 1;
  char *from = (char *)alloca (maxlen);
  char *to = (char *)alloca (maxlen);
  struct_stat sb;
  int i;

  if (stat (fname, &sb) == 0)
    if (S_ISREG (sb.st_mode) == 0)
      return;

  for (i = opt.backups; i > 1; i--)
    {
      sprintf (from, "%s.%d", fname, i - 1);
      sprintf (to, "%s.%d", fname, i);
      rename (from, to);
    }

  sprintf (to, "%s.%d", fname, 1);
  rename(fname, to);
}

static bool no_proxy_match (const char *, const char **);

/* Return the URL of the proxy appropriate for url U.  */

static char *
getproxy (struct url *u)
{
  char *proxy = NULL;
  char *rewritten_url;
  static char rewritten_storage[1024];

  if (!opt.use_proxy)
    return NULL;
  if (no_proxy_match (u->host, (const char **)opt.no_proxy))
    return NULL;

  switch (u->scheme)
    {
    case SCHEME_HTTP:
      proxy = opt.http_proxy ? opt.http_proxy : getenv ("http_proxy");
      break;
#ifdef HAVE_SSL
    case SCHEME_HTTPS:
      proxy = opt.https_proxy ? opt.https_proxy : getenv ("https_proxy");
      break;
#endif
    case SCHEME_FTP:
      proxy = opt.ftp_proxy ? opt.ftp_proxy : getenv ("ftp_proxy");
      break;
    case SCHEME_INVALID:
      break;
    }
  if (!proxy || !*proxy)
    return NULL;

  /* Handle shorthands.  `rewritten_storage' is a kludge to allow
     getproxy() to return static storage. */
  rewritten_url = rewrite_shorthand_url (proxy);
  if (rewritten_url)
    {
      strncpy (rewritten_storage, rewritten_url, sizeof (rewritten_storage));
      rewritten_storage[sizeof (rewritten_storage) - 1] = '\0';
      proxy = rewritten_storage;
    }

  return proxy;
}

/* Returns true if URL would be downloaded through a proxy. */

bool
url_uses_proxy (const char *url)
{
  bool ret;
  struct url *u = url_parse (url, NULL);
  if (!u)
    return false;
  ret = getproxy (u) != NULL;
  url_free (u);
  return ret;
}

/* Should a host be accessed through proxy, concerning no_proxy?  */
static bool
no_proxy_match (const char *host, const char **no_proxy)
{
  if (!no_proxy)
    return false;
  else
    return sufmatch (no_proxy, host);
}