commit aeb1398411ce245fa7982365640f7852d63b3d52
parent dbb7f7b66d2d10a4bf14a404b66fa20cbf8a02ca
Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date: Sat, 4 Feb 2023 12:34:56 +0100
README: describe how to add new parsed tags and fields to sfeed.c
Diffstat:
| M | README | | | 90 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
1 file changed, 90 insertions(+), 0 deletions(-)
diff --git a/README b/README
@@ -1070,6 +1070,96 @@ file:
- - -
+sfeed.c: adding new XML tags or sfeed(5) fields to the parser
+-------------------------------------------------------------
+
+sfeed.c contains definitions to parse XML tags and map them to sfeed(5) TSV
+fields. Parsed RSS and Atom tag names are first stored as a TagId, which is a
+number. This TagId is then mapped to the output field index.
+
+* Add a new TagId enum for the tag.
+
+* (optional) Add a new FeedField* enum for the new output field or you can map
+ it to an existing field.
+
+* Add the new XML tag name to the array variable of parsed RSS or Atom
+ tags: rsstags[] or atomtags[].
+
+ These must be defined in alphabetical order, because a binary search is used
+ which uses the strcasecmp() function.
+
+* Add the parsed TagId to the output field in the array variable fieldmap[].
+
+ When another tag is also mapped to the same output field then the tag with
+ the highest TagId number value overrides the mapped field: the order is from
+ least important to high.
+
+* If this defined tag is just using the inner data of the XML tag, then this
+ definition is enough. If it for example has to parse a certain attribute you
+ have to add a check for the TagId to the xmlattr() callback function.
+
+* (optional) Print the new field in the printfields() function.
+
+Below is a patch example to add the MRSS "media:content" field as a new field:
+
+diff --git a/sfeed.c b/sfeed.c
+--- a/sfeed.c
++++ b/sfeed.c
+@@ -50,7 +50,7 @@ enum TagId {
+ RSSTagGuidPermalinkTrue,
+ /* must be defined after GUID, because it can be a link (isPermaLink) */
+ RSSTagLink,
+- RSSTagEnclosure,
++ RSSTagMediaContent, RSSTagEnclosure,
+ RSSTagAuthor, RSSTagDccreator,
+ RSSTagCategory,
+ /* Atom */
+@@ -81,7 +81,7 @@ typedef struct field {
+ enum {
+ FeedFieldTime = 0, FeedFieldTitle, FeedFieldLink, FeedFieldContent,
+ FeedFieldId, FeedFieldAuthor, FeedFieldEnclosure, FeedFieldCategory,
+- FeedFieldLast
++ FeedFieldMediaContent, FeedFieldLast
+ };
+
+ typedef struct feedcontext {
+@@ -137,6 +137,7 @@ static const FeedTag rsstags[] = {
+ { STRP("enclosure"), RSSTagEnclosure },
+ { STRP("guid"), RSSTagGuid },
+ { STRP("link"), RSSTagLink },
++ { STRP("media:content"), RSSTagMediaContent },
+ { STRP("media:description"), RSSTagMediaDescription },
+ { STRP("pubdate"), RSSTagPubdate },
+ { STRP("title"), RSSTagTitle }
+@@ -180,6 +181,7 @@ static const int fieldmap[TagLast] = {
+ [RSSTagGuidPermalinkFalse] = FeedFieldId,
+ [RSSTagGuidPermalinkTrue] = FeedFieldId, /* special-case: both a link and an id */
+ [RSSTagLink] = FeedFieldLink,
++ [RSSTagMediaContent] = FeedFieldMediaContent,
+ [RSSTagEnclosure] = FeedFieldEnclosure,
+ [RSSTagAuthor] = FeedFieldAuthor,
+ [RSSTagDccreator] = FeedFieldAuthor,
+@@ -677,6 +679,8 @@ printfields(void)
+ string_print_uri(&ctx.fields[FeedFieldEnclosure].str);
+ putchar(FieldSeparator);
+ string_print_trimmed_multi(&ctx.fields[FeedFieldCategory].str);
++ putchar(FieldSeparator);
++ string_print_trimmed(&ctx.fields[FeedFieldMediaContent].str);
+ putchar('\n');
+
+ if (ferror(stdout)) /* check for errors but do not flush */
+@@ -718,7 +722,7 @@ xmlattr(XMLParser *p, const char *t, size_t tl, const char *n, size_t nl,
+ }
+
+ if (ctx.feedtype == FeedTypeRSS) {
+- if (ctx.tag.id == RSSTagEnclosure &&
++ if ((ctx.tag.id == RSSTagEnclosure || ctx.tag.id == RSSTagMediaContent) &&
+ isattr(n, nl, STRP("url"))) {
+ string_append(&tmpstr, v, vl);
+ } else if (ctx.tag.id == RSSTagGuid &&
+
+- - -
+
Running custom commands inside the sfeed_curses program
-------------------------------------------------------
