commit aeb1398411ce245fa7982365640f7852d63b3d52
parent dbb7f7b66d2d10a4bf14a404b66fa20cbf8a02ca
Author: Hiltjo Posthuma <[email protected]>
Date: Sat, 4 Feb 2023 12:34:56 0100
README: describe how to add new parsed tags and fields to sfeed.c
Diffstat:
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
-------------------------------------------------------
