jadedctrl/ feedsnake
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Support for updating feeds with UNIX client 

Adds the --update (-u) and --since-update options, for updating a feed
file in-place (assuming the xdg.origin.url attr is set).
This commit is contained in:
Jaidyn Ann 2022-12-27 12:32:57 -06:00
parent d9eb86434c
commit 2269ac403f
1 changed files with 54 additions and 25 deletions
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79
feedsnake.scm
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@ -27,6 +27,7 @@
(chicken base)
srfi-19)
;; Just car's the value of alist-ref (if it exists)
(define (alist-car-ref key alist)
(let ([value (alist-ref key alist)])
@ -51,7 +52,7 @@
;; The main feedsnake module; parses atom feeds into alists and strings
(module feedsnake
(updated-feed-string read-feed filter-entries write-entry
(updated-feed-string read-feed filter-entries write-entry update-feed-file
write-entry-to-file write-entries-to-file all-entries entry->string
*maildir-template* *mbox-template*)
@ -135,19 +136,13 @@
;; Returns either the updated string of a feed (in comparison to old string),
;; or #f if literally nothing's changed
(define (updated-feed-string url old-string)
(let* ([new-string (fetch-feed-string url)]
(let* ([new-string (fetch-http-string url)]
[updated? (not (eq? (hash old-string) (hash new-string)))])
(if updated?
new-string
#f)))
;; Download a feed (AKA fetch over HTTP to a string)
(define (fetch-feed-string url)
(call-with-output-string
(lambda (out) (fetch-http url out))))
(define (entry->string entry template)
(named-format
template
@ -249,11 +244,11 @@
;; Switch the cached version of the feed with a newer version, if available
(define (update-feed-file feed-path)
(define (update-feed-file feed-path feed-url)
(let* ([old-string (call-with-input-file feed-path
(lambda (in-port) (read-string #f in-port)))]
[new-string (updated-feed-string
(get-xattr feed-path "user.xdg.origin.url")
feed-url
old-string)])
(if new-string
(call-with-output-file feed-path
@ -338,6 +333,12 @@
(lambda (in-port) (copy-port in-port out-port))))
;; Download a feed (AKA fetch over HTTP to a string)
(define (fetch-http-string url)
(call-with-output-string
(lambda (out) (fetch-http url out))))
) ;; feedsnake module
@ -379,6 +380,9 @@
"Output file, used for mbox output. Default is stdout ('-')."
(single-char #\o)
(value (required FILE)))
(update
"Update feeds by downloading new versions to the same path."
(single-char #\u))
(since
"Output entries after the given date, in YYYY-MM-DD hh:mm:ss format."
(single-char #\s)
@ -386,8 +390,10 @@
(since-last
"Output entries dating from the last saved parsing of the file."
(single-char #\S))
(since-update
"Output entries dating from the last update of the file.")
(no-save-date
"Don't save the date of this parsing in cache; to avoid influencing since-last."
"Don't save the date of this parse/update in cache; to avoid influencing since-*."
(single-char #\n))))
@ -397,6 +403,7 @@
(write-string (usage *opts*) #f (open-output-file* fileno/stderr)))
;; Wrap around the main function, so that the user isn't scared off by exceptions
(define-syntax exception-condom
(syntax-rules ()
((exception-condom expr)
@ -405,7 +412,7 @@
(write-string
(string-append (get-condition-property exn 'exn 'message)
" ("
(symbol->string (get-condition-property exn 'exn 'location))
;; (symbol->string (get-condition-property exn 'exn 'location))
")\n")
#f (open-output-file* fileno/stderr))
(exit 2))
@ -421,14 +428,14 @@
;; The `main` procedure that should be called to run feedsnake-unix for use as script.
(define (main)
(exception-condom
;; (exception-condom
(let* ([args (getopt-long (command-line-arguments) *opts*)]
[free-args (alist-ref '@ args)])
(if (alist-ref 'help args)
(help)
(map (lambda (feed-pair)
(process-feed args feed-pair))
(get-feeds free-args))))))
(get-feeds free-args)))))
;; Turn the scripts free-args into parsed Feedsnake feed alists
@ -445,25 +452,40 @@
(let ([feed
(if (string=? feed-path "-")
(call-with-input-string (read-string) read-feed)
(call-with-input-file feed-path read-feed))])
(ignore-errors (call-with-input-file feed-path read-feed)))])
(list feed-path feed)))
;; Process a parsed feed, given arguments passed to the script
(define (process-feed args feed-pair)
(let* ([feed (last feed-pair)]
[feed-path (first feed-pair)]
[feed-path (first feed-pair)])
;; Update the feed
(if (alist-ref 'update args)
(begin
(update-feed-file feed-path
(get-xattr feed-path "user.xdg.origin.url"))
(set! feed (call-with-input-file feed-path read-feed))
(if (not (alist-ref 'no-save-date args))
(set-xattr feed-path "user.feedsnake.updated"
(date->rfc339-string (current-date-utc))))))
;; Save the parsing date, unless the user doesn't want that
(if (and (file-exists? feed-path)
(not (alist-ref 'no-save-date args)))
(set-xattr feed-path "user.feedsnake.parsed"
(date->rfc339-string (current-date-utc))))
(output-entries args `(,feed-path ,feed))))
;; Output the appropriate entrise of the given feed, using script's args
(define (output-entries args feed-pair)
(let* ([feed (last feed-pair)]
[output-dir (alist-ref 'outdir args)]
[output (or (alist-ref 'output args) output-dir)]
[template (if output-dir *maildir-template* *mbox-template*)]
[filter (entry-filter feed-pair args)])
;; Save the parsing date, unless the user doesn't want that
(if (and (file-exists? (first feed-pair))
(not (alist-ref 'no-save-date args)))
(set-xattr (first feed-pair) "user.feedsnake.parsed"
(date->rfc339-string (current-date-utc))))
(cond
[output
(write-entries-to-file (filter-entries feed filter) template output)]
@ -483,19 +505,26 @@
[entry-date (lambda (entry)
(or (alist-car-ref 'updated entry)
(alist-car-ref 'published entry)))]
[last-string (or (ignore-errors
[last-parse-string (or (ignore-errors
(get-xattr (first feed-pair) "user.feedsnake.parsed"))
"1971-01-01T00:00:00Z")]
[last-update (rfc339-string->date last-string)])
[last-parse (rfc339-string->date last-parse-string)]
[last-update-string (or (ignore-errors
(get-xattr (first feed-pair) "user.feedsnake.updated"))
"1971-01-01T00:00:00Z")]
[last-update (rfc339-string->date last-update-string)])
(lambda (entry)
(cond [since
(date>=? (entry-date entry) since)]
[(alist-ref 'since-last args)
(date>=? (entry-date entry) last-parse)]
[(alist-ref 'since-update args)
(date>=? (entry-date entry) last-update)]
[#t
#t]))))
;; Supposed config root of the user (as per XDG, or simple ~/.config)
(define (config-directory)
(or (get-environment-variable "XDG_CONFIG_HOME")