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diff --git a/docs/CRAWL.announce b/docs/CRAWL.announce new file mode 100644 index 0000000..e734bcb --- /dev/null +++ b/docs/CRAWL.announce @@ -0,0 +1,131 @@ +The TRAVERSAL code from old versions of Lynx has been upgraded by David +Mathog (mathog@seqaxp.bio.caltech.edu) so that it works again, can be +implemented via a command line switch (-traversal) instead of via a +compilation symbol for creating a separate Lynx executable as in those +previous versions, and can be used in conjunction with a -crawl switch +to make Lynx a front end for a Web Crawler. + + +Usage: + + lynx [-traversal] [-realm] [-crawl] ["startpage"] + + +Added switches are: + + -traversal Follow all http links derived from startpage that are + on the same server as startpage. If startpage isn't + specified then the traversal begins with the default + startfile or WWW_HOME. + + -realm Further restrict http links to ones in the same realm + (having a matching base URI) as the startpage (e.g., + http://host/~user/ will restrict the traversal to that + user's public html tree). + + -crawl With [-traversal] outputs each unique hypertext page + as an lnk###########.dat file in the format specified + below. With [-dump] outputs only the startpage, in + the same format, to stdout. + + +Note on startpage: + + If a startpage is specified and contains any uppercase + characters, on VMS it should be enclosed in double-quotes. + The code that extracts the access and host fields from + startpage for comparsions with links to ensure they are + not on another server, and the comparisons with already + traversed links, are case sensitive, and the startpage + will go to all lowercase on VMS if no double-quotes are + supplied, such that it might be treated as a new link if + encounted with uppercase letters. + + +Files created and/or used with the -traversal switch, based on definitions +in userdefs.h: + +TRAVERSE_FILE (traverse.dat): + Contains a list of all URLs that were traversed. Note + that if a URL appears in this file it will not be + traversed again (important if runs are started and + stopped). Placing an entry in this file BEFORE the + run will block traversal of that URL. Unlike reject.dat + a final * has no effect (see below). Note that Lynx + internal client-side image MAP URLs will be included in + this file (e.g., LYNXIMGMAP:http://server/foo.html#map1), + in addition to the "real" (external) http URLs. + +TRAVERSE_FOUND_FILE (traverse2.dat): + Contains a list of all URLs that were traversed, in the + order encountered or re-encountered (but not re-travered) + during a traversal run, and the TITLEs of the documents + (separated from the URLs by TABs) A URL and TITLE may be + present in this list many times. To simplify the list, + on VMS use: sort/nodups traverse2.dat;1 ;2 + Note that the URLs and TITLEs of the Lynx internal + client-side image MAP pseudo-documents will not be + included in this file, though "traversed", but only the + http URLs and TITLEs derived from the MAP's AREA tag + HREFs that were traversed. + +TRAVERSE_REJECT_FILE (reject.dat): + Contains a list of URLs that have been rejected from the + traversal. Once a URL has been entered in this list, it + will not be traversed. URLs that end in a * will cause + rejection of all URLs that match up to the character before + the *. So for instance, to reject all htbin references on a + site put this line in the reject.dat file BEFORE starting + the run: http://www.site.wherever:8000/htbin* + +TRAVERSE_ERRORS (traverse.errors): + A list of links that could not be accessed or had an + unknown status returned by the http server. If the + owner of the document containing the link is know via + a LINK REV="made" HREF="mailto:foo" in it and the + MAIL_SYSTEM_ERROR_LOGGING was set true in userdefs.h + or lynx.cfg (not recommended!!!), a message about the + problem will be mailed to the owner as well. + + +Files created during traversals if the -crawl switch is included with the +-traversal switch: + +lnk########.dat Numbered output files containing the contents of traversed + hypertext documents in text format. All hypertext links + within the document have been stripped, and the URL and + TITLE of the document are recorded as the first two lines, + e.g., for the seqaxp.bio.caltech.edu home page the first + two lines will be: + + THE_URL:http://seqaxp.bio.caltech.edu:8000/ + THE_TITLE:SAF Web server home page + + The VMSIndex software is being adapted to use this + information to extract the corresponding URL and TITLE + for use in indexing the lnk########.dat files, e.g.: + + $ build_index - + /url=(text="THE_URL:") - + /topic=(text="THE_TITLE:",EXCLUDE) - + /output=INDEX_NAME - + lnk*.dat + + A clever person should be able to figure out a way to + index the lnk########.dat files on Unix as well. + + If you want the hypertext links in the document to be + numbered, include the -number_links switch. By default, + this will cause the list of References (URLs for the + numbered links) to be appended as well. If you want + numbered links but not the References list, include the + -nolist switch as well. + + Note that any client-side image MAP pseudo documents + that were "traversed" will not have lnk########.dat + output files created for them, but output files will + be created for "real" documents that were traversed + based on the HREFs of the MAP's AREA tags. + +This functionality is still under development. Feedback and suggestions +are welcome. |