dotfiles/bin/httpcompression

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2013-06-23 06:03:36 +00:00
#!/usr/bin/env bash
# Test if HTTP compression (RFC 2616 + SDCH) is enabled for a given URL
# https://github.com/mathiasbynens/dotfiles/blob/master/bin/httpcompression
declare -r hUA="Mozilla/5.0 Gecko"
declare -r hAE="Accept-Encoding: gzip, deflate, sdch"
declare -r maxConTime=15
declare -r maxTime=30
declare availDicts="" dict="" dictClientID="" dicts="" headers="" i="" \
indent="" url="" encoding="" urlHeaders=""
headers="$( curl --connect-timeout $maxConTime \
-A "$hUA" `# Send a fake UA string for sites
# that sniff it instead of using
# the Accept-Encoding header` \
-D - `# Get response headers` \
-H "$hAE" \
-L `# If the page was moved to a different
# location, redo the request` \
-m $maxTime \
-s `# Don\'t show the progress meter` \
-S `# Show error messages` \
-o /dev/null `# Ignore content` \
"$1" )" \
&& ( \
url="$1"
# Iterate over the headers of all redirects
while [ -n "$headers" ]; do
# Get headers for the "current" URL
urlHeaders="$( printf "%s" "$headers" |
sed -n '1,/^HTTP/p' )"
# Remove the headers for the "current" URL
headers="${headers/"$urlHeaders"/}"
# ----------------------------------------------------------------------
# | SDCH |
# ----------------------------------------------------------------------
# SDCH Specification:
# - www.blogs.zeenor.com/wp-content/uploads/2011/01/Shared_Dictionary_Compression_over_HTTP.pdf
# Check if the server advertised any dictionaries
dicts="$( printf "%s" "$urlHeaders" |
grep -i 'Get-Dictionary:' |
cut -d':' -f2 |
sed s/,/\ /g )"
if [ -n "$dicts" ]; then
availDicts=""
dict=""
for i in $dicts; do
# Check If the dictionary location is specified as a path,
# and if so, construct it's URL from the host name of the
# referrer URL
[[ "$i" != http* ]] \
&& dict="$(printf "$url" |
sed -En 's/([^/]*\/\/)?([^/]*)\/?.*/\1\2/p')"
dict="$dict$i"
# Request the dictionaries from the server and
# construct the `Avail-Dictionary` header value
#
# [ The user agent identifier for a dictionary is defined
# as the URL-safe base64 encoding (as described in RFC
# 3548, section 4 [RFC3548]) of the first 48 bits (bits
# 0..47) of the dictionary's SHA-256 digest ]
#
dictClientID="$( curl --connect-timeout $maxConTime \
-A "$hUA" -LsS -m $maxTime "$dict" |
openssl dgst -sha256 -binary |
openssl base64 |
cut -c 1-8 |
sed -e 's/\+/-/' -e 's/\//_/' )"
[ -n $availDicts ] && availDicts="$adics,$dictClientID" \
|| availDicts="$dictClientID"
done
# Redo the request (advertising the available dictionaries)
# and replace the old resulted headers with the new ones
urlHeaders="$( curl --connect-timeout $maxConTime \
-A "$hUA" -D - -H "$hAE" \
-H "Avail-Dictionary: $availDicts" \
-m $maxTime -o /dev/null -sS "$1" )"
fi
# ----------------------------------------------------------------------
# Get the content encoding header values
encoding="$( printf "%s" "$urlHeaders" |
grep -i 'Content-Encoding:' |
cut -d' ' -f2 |
tr "\r" "," |
tr -d "\n" |
sed 's/,$//' )"
[ -n "$encoding" ] && encoding="[$encoding]"
# Print the output for the "current" URL
if [ "$url" != "$1" ]; then
printf "%s\n" "$indent$url $encoding"
indent=" "$indent
else
printf "\n%s\n" " $1 $encoding"
indent=" ↳"
fi
# Get the next URL value
url="$( printf "%s" "$urlHeaders" |
grep -i 'Location' |
sed -e 's/Location://' |
tr -d '\r' )"
done
printf "\n"
) || printf ""