#!/bin/sh -e
#
# # DASHT-SERVER-HTTP 1 2020-05-16 2.4.0
#
# ## NAME
#
# dasht-server-http - simple search engine that powers dasht-server(1)
#
# ## SYNOPSIS
#
# `dasht-server-http`
#
# ### Examples
#
# printf 'GET / HTTP/1.1\r\n' | `dasht-server-http`
# Shows topics (A-Z) from each installed [Dash] docset.
#
# printf 'GET /?docsets=*DOCSETS* HTTP/1.1\r\n' | `dasht-server-http`
# Shows topics (A-Z) from installed [Dash] docsets matching *DOCSETS*.
#
# printf 'GET /?query=*PATTERN* HTTP/1.1\r\n' | `dasht-server-http`
# Searches for *PATTERN* in all installed [Dash] docsets.
#
# printf 'GET /?query=*PATTERN*&docsets=*DOCSETS* HTTP/1.1\r\n' | `dasht-server-http`
# Searches for *PATTERN* in installed [Dash] docsets matching *DOCSETS*.
#
# ## DESCRIPTION
#
# Reads a single HTTP request from stdin and writes a HTTP response to stdout.
# Any `query=`*PATTERN* and `docsets=`*DOCSETS* parameters in the request URL
# are passed to dasht-query-html(1) as its *PATTERN* and *DOCSETS* arguments.
#
# ## ENVIRONMENT
#
# `DASHT_DOCSETS_DIR`
# Defines the filesystem location where your [Dash] docsets are installed.
# If undefined, its value is assumed to be `$XDG_DATA_HOME/dasht/docsets/`
# or, if `XDG_DATA_HOME` is undefined, `$HOME/.local/share/dasht/docsets/`.
#
# ## SEE ALSO
#
# dasht-query-html(1), dasht-server(1), dasht-docsets(1), dasht(1), [Dash]
#
# [Dash]: https://kapeli.com/dash
#
# ## AUTHOR
#
# Written in 2016 by Suraj N. Kurapati <https://github.com/sunaku/dasht>
# Distributed under the terms of the ISC license (refer to README file).
# Escapes XML "predefined entities" in given arguments.
# See http://www.w3.org/TR/REC-xml/#sec-predefined-ent
entities() {
echo "$*" |
sed -e 's/&/\&/g' \
-e 's/"/\"/g' \
-e "s/'/\'/g" \
-e 's/</\</g' \
-e 's/>/\>/g'
}
# Converts the given 2-xdigit string into a byte value.
# See http://mywiki.wooledge.org/BashFAQ/071
hex2byte() {
dec=$(( 0x$1 ))
oct=$(printf '%03o' "$dec")
printf "\\$oct"
}
# parse URL from request: only GET is supported
url=$(awk '
/^GET [[:print:]]+ HTTP\/1.+\r$/ { print $2 }
/^\r$/ { exit } # reached end of HTTP request
')
# serve translated local file:// URLs over HTTP
# (skip the / homepage and /? form submissions)
if ! test "$url" = / -o -z "${url##/\?*}"; then
file=${url%#*} # strip URI fragment, if any
if test -f "$file"; then
printf 'HTTP/1.0 200 OK\r\n'
printf 'Content-Type: %s\r\n' "$(file -b --mime "$file" 2>&1)"
printf '\r\n'
cat "$file" 2>&1 || :
else
printf 'HTTP/1.0 400 Bad Request\r\n'
printf '\r\n'
fi
exit
fi
# parse URL query parameters as shell variables
eval "$(
# split URL on query parameter delimiters (?&)
IFS='?&'
set -- $url
shift # protocol, hostname, port number, path
# convert segments into safely eval()able assignments
for segment; do
# split param=value
param=${segment%%=*}
value=${segment#*=}
# only accept known parameters to prevent injection
case "$param" in (query|docsets)
# decode URL-encoded characters in parameter value
value=$(echo "$value" | tr '+' ' ' | # + is space
sed 's/%\([[:xdigit:]]\{2\}\)/$(hex2byte \1)/g')
if test -n "$value"; then
echo "$param=\"\$$param\${$param:+ }$value\""
echo "${param}_html=\$(entities \"\$$param\")"
fi
;;esac
done
)"
# emit response header
printf 'HTTP/1.0 200 OK\r\n'
printf 'Content-Type: text/html\r\n'
printf '\r\n'
# emit response body
docsets_menu=$(
{ dasht-docsets # all installed docsets
dasht-docsets $docsets # the current selection
} | sort | uniq -c | awk '{ $1 = $1 > 1; print }'
)
set -- $(echo "$docsets_menu" | awk '
BEGIN { matched = ignored = 0 }
$1 { matched++ }
!$1 { ignored++ }
END { print matched, ignored, NR }
')
cat <<HEADER
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>dasht $query_html $docsets_html</title>
<style>
body, input, select {
font-family: monospace;
}
form {
display: flex;
}
tr:hover {
background-color: LightYellow;
}
a {
text-decoration: none;
}
a:hover {
text-decoration: underline;
}
b > i > u {
text-decoration: none;
font-style: normal;
font-weight: normal;
color: Black;
background-color: Yellow;
border: thin dotted Silver;
}
h1 > i {
color: red;
}
</style>
</head>
<body>
<form method="get" action="/">
<div>
<label>Search for
<input name="query" value="$query_html" type="search"
placeholder="space is wildcard" autofocus>
</label>
<br>
<label>in docsets
<select name="docsets">
<option value="" selected>matched $1 out of $3</option>
$(echo "$docsets_menu" | awk -v were_any_ignored=$2 '{
label = were_any_ignored && $1 ? "((( " $2 " )))" : $2
regex = $2; gsub("[[:punct:]]", "\\\\&", regex)
value = "^" regex "$"
print "<option value=\"" value "\">" label "</option>"
}')
</select>
</label>
<br>
<label>with names
<input name="docsets" value="$docsets_html" type="search"
placeholder="chosen from above">
</label>
<br>
</div>
<input type="submit">
</form>
<br>
HEADER
if test $1 -eq 0; then
# notify user when no docsets are installed so they can go install them
echo "<h1><i>${docsets_html}</i> docsets not installed so <i>$query_html</i> not searched</h1>"
elif results_html=$(dasht-query-html "$query" $docsets); then
# translate local file:// URLs into HTTP ones so that we can serve them
echo "$results_html" | sed 's,file://,,'
else
# notify user when no results are found so they can refine their search
echo "<h1><i>$query_html</i> not found in $1 docsets matching <i>${docsets_html:-.*}</i></h1>"
fi
cat <<FOOTER
</body>
</html>
FOOTER