commit ec7abe8b5ea4c56bd442f536544c4dde4b38a847
parent 4b99778344bca3a1606046b5bf1087160ea1661c
Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date: Sun, 27 Oct 2024 09:23:53 +0100
documentation improvements
- Add ETag example to sfeedrc.5 man page.
This was in the README but now also added to the man page for visibility.
- Indent code examples to separate leading text from code examples.
- Some textual improvements.
Diffstat:
9 files changed, 129 insertions(+), 61 deletions(-)
diff --git a/README b/README
@@ -639,9 +639,9 @@ RSS/Atom data or change the default curl options:
- - -
-Caching, incremental data updates and bandwidth-saving
+Caching, incremental data updates and bandwidth saving
-For servers that support it some incremental updates and bandwidth-saving can
+For servers that support it some incremental updates and bandwidth saving can
be done by using the "ETag" HTTP header.
Create a directory for storing the ETags per feed:
diff --git a/sfeed.1 b/sfeed.1
@@ -1,4 +1,4 @@
-.Dd January 7, 2023
+.Dd October 27, 2024
.Dt SFEED 1
.Os
.Sh NAME
@@ -52,51 +52,51 @@ Item, categories, multiple values are separated by the '|' character.
.Sh EXIT STATUS
.Ex -std
.Sh EXAMPLES
-.Bd -literal
+.Bd -literal -offset 4n
curl -s 'https://codemadness.org/atom.xml' | sfeed
.Ed
.Pp
To convert the character set from a feed that is not UTF-8 encoded the
.Xr iconv 1
tool can be used:
-.Bd -literal
+.Bd -literal -offset 4n
curl -s 'https://codemadness.org/some_iso-8859-1_feed.xml' | \e
iconv -f iso-8859-1 -t utf-8 | \e
sfeed
.Ed
.Sh EXAMPLE SETUP
1. Create a directory for the sfeedrc configuration and the feeds:
-.Bd -literal
- mkdir -p ~/.sfeed/feeds
+.Bd -literal -offset 4n
+mkdir -p ~/.sfeed/feeds
.Ed
.Pp
2. Copy the example
.Xr sfeedrc 5
configuration:
-.Bd -literal
- cp sfeedrc.example ~/.sfeed/sfeedrc
- $EDITOR ~/.sfeed/sfeedrc
+.Bd -literal -offset 4n
+cp sfeedrc.example ~/.sfeed/sfeedrc
+$EDITOR ~/.sfeed/sfeedrc
.Ed
.Pp
Or import existing OPML subscriptions using
.Xr sfeed_opml_import 1 :
-.Bd -literal
- sfeed_opml_import < file.opml > ~/.sfeed/sfeedrc
+.Bd -literal -offset 4n
+sfeed_opml_import < file.opml > ~/.sfeed/sfeedrc
.Ed
.Pp
3. To update feeds and merge the new items with existing items:
-.Bd -literal
- sfeed_update
+.Bd -literal -offset 4n
+sfeed_update
.Ed
.Pp
4. Format feeds to a plain-text list:
-.Bd -literal
- sfeed_plain ~/.sfeed/feeds/*
+.Bd -literal -offset 4n
+sfeed_plain ~/.sfeed/feeds/*
.Ed
.Pp
Or format feeds to a curses interface:
-.Bd -literal
- sfeed_curses ~/.sfeed/feeds/*
+.Bd -literal -offset 4n
+sfeed_curses ~/.sfeed/feeds/*
.Ed
.Pp
There are also other formatting programs included.
diff --git a/sfeed_content.1 b/sfeed_content.1
@@ -1,4 +1,4 @@
-.Dd December 22, 2021
+.Dd October 27, 2024
.Dt SFEED_CONTENT 1
.Os
.Sh NAME
@@ -35,12 +35,13 @@ If it is not set it will use lynx by default.
.Sh EXIT STATUS
.Ex -std
.Sh EXAMPLES
-.Bd -literal
+Example:
+.Bd -literal -offset 4n
curl -s 'https://codemadness.org/atom_content.xml' | sfeed | sfeed_content
.Ed
.Pp
-The output format looks like this:
-.Bd -literal
+The output format will look like this:
+.Bd -literal -offset 4n
Title: The title.
Author: The line with the author if it is set.
Category: The line with the categories if it is set.
diff --git a/sfeed_curses.1 b/sfeed_curses.1
@@ -1,4 +1,4 @@
-.Dd August 1, 2023
+.Dd October 27, 2024
.Dt SFEED_CURSES 1
.Os
.Sh NAME
@@ -299,14 +299,15 @@ When plumbing an URL then stdin is closed also.
.Ex -std
The exit status is 130 on SIGINT and 143 on SIGTERM.
.Sh EXAMPLES
-.Bd -literal
+Example:
+.Bd -literal -offset 4n
sfeed_curses ~/.sfeed/feeds/*
.Ed
.Pp
Another example which shows some of the features
.Nm
has:
-.Bd -literal
+.Bd -literal -offset 4n
export SFEED_AUTOCMD="2tgo"
export SFEED_URL_FILE="$HOME/.sfeed/urls"
[ -f "$SFEED_URL_FILE" ] || touch "$SFEED_URL_FILE"
@@ -316,7 +317,7 @@ sfeed_curses ~/.sfeed/feeds/*
Which does the following:
.Bl -enum
.It
-Set commands to execute automatically:
+Set commands to execute automatically on startup:
.Pp
Set the current layout to a horizontal mode ('2' keybind).
Showing a feeds sidebar on the top and the feed items on the bottom.
diff --git a/sfeed_markread.1 b/sfeed_markread.1
@@ -1,4 +1,4 @@
-.Dd July 25, 2021
+.Dd October 27, 2024
.Dt SFEED_MARKREAD 1
.Os
.Sh NAME
@@ -31,13 +31,16 @@ plain-text list of read URLs.
.Sh EXIT STATUS
.Ex -std
.Sh EXAMPLES
-.Bd -literal
+Example:
+.Bd -literal -offset 4n
export SFEED_URL_FILE="$HOME/.sfeed/urls"
echo 'https://codemadness.org/sfeed.html' | sfeed_markread read
.Ed
.Pp
-or
-.Bd -literal
+or pass the
+.Ar urlfile
+as a parameter:
+.Bd -literal -offset 4n
echo 'https://codemadness.org/sfeed.html' | sfeed_markread read ~/.sfeed/urls
.Ed
.Sh SEE ALSO
diff --git a/sfeed_mbox.1 b/sfeed_mbox.1
@@ -1,4 +1,4 @@
-.Dd August 4, 2021
+.Dd October 27, 2024
.Dt SFEED_MBOX 1
.Os
.Sh NAME
@@ -47,14 +47,15 @@ By default this is set to "0".
.Sh EXIT STATUS
.Ex -std
.Sh EXAMPLES
-.Bd -literal
+Example:
+.Bd -literal -offset 4n
sfeed_mbox ~/.sfeed/feeds/*
.Ed
.Pp
-To include the content.
+Below is an example to include the content.
This can be insecure for some of the mail clients that interpret HTML code in
an unsafe way:
-.Bd -literal
+.Bd -literal -offset 4n
SFEED_MBOX_CONTENT=1 sfeed_mbox ~/.sfeed/feeds/*
.Ed
.Sh SEE ALSO
diff --git a/sfeed_update.1 b/sfeed_update.1
@@ -1,4 +1,4 @@
-.Dd August 1, 2023
+.Dd October 27, 2024
.Dt SFEED_UPDATE 1
.Os
.Sh NAME
@@ -35,7 +35,7 @@ man page for a detailed description of the format and an example file.
.El
.Sh FILES WRITTEN
.Bl -tag -width Ds
-.It feedname
+.It Pa feedname
TAB-separated
.Xr sfeed 5
format containing all items per feed.
@@ -55,7 +55,7 @@ entry-point.
.Sh LOGGING
When processing a feed it will log failures to stderr and non-failures to
stdout in the format:
-.Bd -literal
+.Bd -literal -offset 4n
[HH:MM:SS] feedname message
.Ed
.Sh EXIT STATUS
@@ -63,7 +63,7 @@ stdout in the format:
If any of the feeds failed to update then the exit status is non-zero.
.Sh EXAMPLES
To update your feeds and format them in various formats:
-.Bd -literal
+.Bd -literal -offset 4n
# Update feeds
sfeed_update "configfile"
# Format to a plain-text list
diff --git a/sfeed_web.1 b/sfeed_web.1
@@ -13,8 +13,8 @@ reads the HTML data of the webpage from stdin and writes the found URLs to
stdout.
.Pp
Such a link reference in HTML code looks like:
-.Bd -literal
- <link rel="alternate" href="atom.xml" type="application/atom+xml" />
+.Bd -literal -offset 4n
+<link rel="alternate" href="atom.xml" type="application/atom+xml" />
.Ed
.Sh OPTIONS
.Bl -tag -width 8n
@@ -39,7 +39,7 @@ Usually application/atom+xml or application/rss+xml.
.Ex -std
.Sh EXAMPLES
Get URLs from a website:
-.Bd -literal
+.Bd -literal -offset 4n
curl -s -L 'https://codemadness.org/' | sfeed_web 'https://codemadness.org/'
.Ed
.Sh SEE ALSO
diff --git a/sfeedrc.5 b/sfeedrc.5
@@ -1,4 +1,4 @@
-.Dd December 26, 2023
+.Dd October 30, 2024
.Dt SFEEDRC 5
.Os
.Sh NAME
@@ -7,7 +7,8 @@
.Sh DESCRIPTION
.Nm
is the configuration file for
-.Xr sfeed_update 1 .
+.Xr sfeed_update 1
+and is evaluated as a shellscript.
.Sh VARIABLES
.Bl -tag -width Ds
.It Va sfeedpath
@@ -30,7 +31,8 @@ Inside the
.Fn feeds
function feeds can be defined by calling the
.Fn feed
-function, its arguments are:
+function.
+Its arguments are:
.Bl -tag -width Ds
.It Fa name
Name of the feed, this is also used as the filename for the TAB-separated
@@ -41,16 +43,22 @@ Each
.Fa name
should be unique.
.It Fa feedurl
-URL to fetch the RSS/Atom data from, usually a HTTP or HTTPS URL.
+URL to fetch the RSS/Atom data from.
+This is usually a HTTP or HTTPS URL.
.It Op Fa basesiteurl
Base URL of the feed links.
-This argument allows to fix relative item links.
+This argument allows fixing relative item links.
.Pp
-According to the RSS and Atom specification feeds should always have absolute
-URLs, however this is not always the case in practise.
+According to the RSS and Atom specification, feeds should always have absolute
+URLs, but this is not always the case in practise.
.It Op Fa encoding
-Feeds are decoded from this name to UTF-8, the name should be a usable
-character-set for the
+Feeds are converted from this
+.Ar encoding
+to UTF-8.
+The
+.Ar encoding
+should be a usable
+character-set name for the
.Xr iconv 1
tool.
.El
@@ -58,11 +66,12 @@ tool.
.Sh OVERRIDE FUNCTIONS
Because
.Xr sfeed_update 1
-is a shellscript each function can be overridden to change its behaviour,
-notable functions are:
+is a shellscript each function can be overridden to change its behaviour.
+Notable functions are:
.Bl -tag -width Ds
.It Fn fetch "name" "url" "feedfile"
-Fetch feed from URL and write the data to stdout, its arguments are:
+Fetch feed from URL and write the data to stdout.
+Its arguments are:
.Bl -tag -width Ds
.It Fa name
Specified name in configuration file (useful for logging).
@@ -77,8 +86,8 @@ By default the tool
is used.
.It Fn convertencoding "name" "from" "to"
Convert data from stdin from one text-encoding to another and write it to
-stdout,
-its arguments are:
+stdout.
+Its arguments are:
.Bl -tag -width Ds
.It Fa name
Feed name.
@@ -95,6 +104,7 @@ is used.
Read RSS/Atom XML data from stdin, convert and write it as
.Xr sfeed 5
data to stdout.
+Its arguments are:
.Bl -tag -width Ds
.It Fa name
Name of the feed.
@@ -107,7 +117,8 @@ This argument allows to fix relative item links.
.It Fn filter "name" "url"
Filter
.Xr sfeed 5
-data from stdin and write it to stdout, its arguments are:
+data from stdin and write it to stdout.
+Its arguments are:
.Bl -tag -width Ds
.It Fa name
Feed name.
@@ -117,7 +128,8 @@ URL of the feed.
.It Fn merge "name" "oldfile" "newfile"
Merge
.Xr sfeed 5
-data of oldfile with newfile and write it to stdout, its arguments are:
+data of oldfile with newfile and write it to stdout.
+Its arguments are:
.Bl -tag -width Ds
.It Fa name
Feed name.
@@ -129,7 +141,8 @@ New file.
.It Fn order "name" "url"
Sort
.Xr sfeed 5
-data from stdin and write it to stdout, its arguments are:
+data from stdin and write it to stdout.
+Its arguments are:
.Bl -tag -width Ds
.It Fa name
Feed name.
@@ -140,7 +153,7 @@ URL of the feed.
.Sh EXAMPLES
An example configuration file is included named sfeedrc.example and also
shown below:
-.Bd -literal
+.Bd -literal -offset 4n
#sfeedpath="$HOME/.sfeed/feeds"
# list of feeds to fetch:
@@ -165,8 +178,8 @@ options for fetching the data, the
.Fn fetch
function can be overridden and added at the top of the
.Nm
-file:
-.Bd -literal
+file, for example:
+.Bd -literal -offset 4n
# fetch(name, url, feedfile)
fetch() {
# allow for 1 redirect, set User-Agent, timeout is 15 seconds.
@@ -174,6 +187,55 @@ fetch() {
"$2" 2>/dev/null
}
.Ed
+.Pp
+Caching, incremental data updates and bandwidth saving
+.Pp
+For HTTP servers that support it some bandwidth saving can be done by changing
+some of the default curl options.
+These options can come at a cost of some privacy, because it exposes additional
+metadata from the previous request.
+.Pp
+.Bl -bullet -compact
+.It
+The curl ETag options (--etag-save and --etag-compare) can be used to store and
+send the previous ETag header value.
+curl version 7.73+ is recommended for it to work properly.
+.It
+The curl -z option can be used to send the modification date of a local file as
+a HTTP If-Modified-Since request header.
+The server can then respond if the data is modified or not or respond with only
+the incremental data.
+.It
+The curl --compressed option can be used to indicate the client supports
+decompression.
+Because RSS/Atom feeds are textual XML data this generally compresses very
+well.
+.It
+The example below also sets the User-Agent to sfeed, because some CDNs block
+HTTP clients based on the User-Agent request header.
+.El
+.Pp
+Example:
+.Bd -literal -offset 4n
+etagpath="$HOME/.sfeed/etags"
+mkdir -p "${etagpath}"
+
+# fetch(name, url, feedfile)
+fetch() {
+ etag="${etagpath}/$(basename "$3")"
+
+ curl \e
+ -L --max-redirs 0 \e
+ -H "User-Agent: sfeed" \e
+ -f -s -m 15 \e
+ --compressed \e
+ --etag-save "${etag}" --etag-compare "${etag}" \e
+ -z "${etag}" \e
+ "$2" 2>/dev/null
+}
+.Ed
+.Pp
+The README file has more examples.
.Sh SEE ALSO
.Xr curl 1 ,
.Xr iconv 1 ,
