Shell Script CURL JSON value to variable - json

I was wondering how to parse the CURL JSON output from the server into variables.
Currently, I have -
curl -X POST -H "Content: agent-type: application/x-www-form-urlencoded" https://www.toontownrewritten.com/api/login?format=json -d username="$USERNAME" -d password="$PASSWORD" | python -m json.tool
But it only outputs the JSON from the server and then have it parsed, like so:
{
"eta": "0",
"position": "0",
"queueToken": "6bee9e85-343f-41c7-a4d3-156f901da615",
"success": "delayed"
}
But how do I put - for example the success value above returned from the server into a variable $SUCCESS and have the value as delayed & have queueToken as a variable $queueToken and 6bee9e85-343f-41c7-a4d3-156f901da615 as a value?
Then when I use-
echo "$SUCCESS"
it shows this as the output -
delayed
And when I use
echo "$queueToken"
and the output as
6bee9e85-343f-41c7-a4d3-156f901da615
Thanks!

Find and install jq (https://stedolan.github.io/jq/). jq is a JSON parser. JSON is not reliably parsed by line-oriented tools like sed because, like XML, JSON is not a line-oriented data format.
In terms of your question:
source <(
curl -X POST -H "$content_type" "$url" -d username="$USERNAME" -d password="$PASSWORD" |
jq -r '. as $h | keys | map(. + "=\"" + $h[.] + "\"") | .[]'
)
The jq syntax is a bit weird, I'm still working on it. It's basically a series of filters, each pipe taking the previous input and transforming it. In this case, the end result is some lines that look like variable="value"
This answer uses bash's "process substitution" to take the results of the jq command, treat it like a file, and source it into the current shell. The variables will then be available to use.

Here's an example of Extract a JSON value from a BASH script
#!/bin/bash
function jsonval {
temp=`echo $json | sed 's/\\\\\//\//g' | sed 's/[{}]//g' | awk -v k="text" '{n=split($0,a,","); for (i=1; i<=n; i++) print a[i]}' | sed 's/\"\:\"/\|/g' | sed 's/[\,]/ /g' | sed 's/\"//g' | grep -w $prop`
echo ${temp##*|}
}
json=`curl -s -X GET http://twitter.com/users/show/$1.json`
prop='profile_image_url'
picurl=`jsonval`
`curl -s -X GET $picurl -o $1.png`
A bash script which demonstrates parsing a JSON string to extract a
property value. The script contains a jsonval function which operates
on two variables, json and prop. When the script is passed the name of
a twitter user it attempts to download the user's profile picture.

You could use perl module on command line:
1st, ensure they is installed, under debian based, you could
sudo apt-get install libjson-xs-perl
But for other OS, you could install perl modules via CPAN (the Comprehensive Perl Archive Network):
cpan App::cpanminus
cpan JSON::XS
Note: You may have to run this with superuser privileges.
then:
curlopts=(-X POST -H
"Content: apent-type: application/x-www-form-urlencoded"
-d username="$USERNAME" -d password="$PASSWORD")
curlurl=https://www.toontownrewritten.com/api/login?format=json
. <(
perl -MJSON::XS -e '
$/=undef;my $a=JSON::XS::decode_json <> ;
printf "declare -A Json=\047(%s)\047\n", join " ",map {
"[".$_."]=\"".$a->{$_}."\""
} qw|queueToken success eta position|;
' < <(
curl "${curlopts[#]}" $curlurl
)
)
The line qw|...| let you precise which variables you want to be driven... This could be replaced by keys $a, but could have to be debugged as some characters is forbiden is associative arrays values names.
echo ${Json[queueToken]}
6bee9e85-343f-41c7-a4d3-156f901da615
echo ${Json[eta]}
0

Related

Get specific string line from file bash

I have a file with this kind of text with pattern
[{"foo":"bar:baz:foo*","bar*":"baz*","etc":"etc"},
{"foo2":"bar2:baz2:foo2*","bar2*":"baz2*","etc":"etc"},
{"foo3":"bar3:baz3:foo3*","bar3*":"baz3*","etc":"etc"},
{"foo4":"bar4:baz4:foo4*","bar4*":"baz4*","etc":"etc"}]
I need to take every string like this
{"foo":"bar:baz:foo*","bar*":"baz*","etc":"etc"} and send each of them to some url via curl
for i in text.txt
do (awk,sed,grep etc)
then curl $string
I can't figure out how to get the desired lines properly from the file without unnecessary symbols
I suggest that you can use jq to process your json file. jq is capable of reading json, and formatting output. Here's an example jq script to process your json file (which I unimaginatively call 'jsonfile'):
jq -r '.[] | "curl -d '\'' \(.) '\'' http://restful.com/api " ' jsonfile
Here's the output:
curl -d ' {"foo":"bar:baz:foo*","bar*":"baz*","etc":"etc"} ' http://restful.com/api
curl -d ' {"foo2":"bar2:baz2:foo2*","bar2*":"baz2*","etc":"etc"} ' http://restful.com/api
curl -d ' {"foo3":"bar3:baz3:foo3*","bar3*":"baz3*","etc":"etc"} ' http://restful.com/api
curl -d ' {"foo4":"bar4:baz4:foo4*","bar4*":"baz4*","etc":"etc"} ' http://restful.com/api
Here's what's going on:
We pass three arguments to the jq program: jq -r <script> <inputfile>.
The -r tells jq to output the results in raw format (that is, please don't escape quotes and stuff).
The script looks like this:
.[] | "some string \(.)"
The first . means take the whole json structure and the [] means iterate through each array element in the structure. The | is a filter that processes each element in the array. The filter is to output a string. We are using \(.) to interpolate the whole element passed into the | filter.
Wow... I've never really explained a jq script before (and it shows). But the crux of it is, we are using jq to find each element in the json array and insert it into a string. Our string is this:
curl -d '<the json dictionary array element>' http://restful.com/api
Ok. And you see the output. It works. But wait a second, we only have output. Let's tell the shell to run each line like this:
jq -r '.[] | "curl -d '\'' \(.) '\'' http://restful.com/api " ' jsonfile | bash
By piping the output to bash, we execute each line that we output. Essentially, we are writing a bash script with jq to curl http://restful.com/api passing the json element as the -d data parameter to POST the json element.
Revisiting for single quote issue
#oguz ismail pointed out that bash will explode if there is a single quote in the json input file. This is true. We can avoid the quote by escaping, but we gain more complexity - making this a non-ideal approach.
Here's the problem input (I just inserted a single quote):
[{"foo":"bar:'baz:foo*","bar*":"baz*","etc":"etc"},
{"foo2":"bar2:baz2:foo2*","bar2*":"baz2*","etc":"etc"},
{"foo3":"bar3:baz3:foo3*","bar3*":"baz3*","etc":"etc"},
{"foo4":"bar4:baz4:foo4*","bar4*":"baz4*","etc":"etc"}]
Notice above that baz is now 'baz. The problem is that a single single quote makes the bash shell complain about unmatched quotes:
$ jq -r '.[] | "curl -d '\'' \(.) '\'' http://restful.com/api " ' jsonfile | bash
bash: line 4: unexpected EOF while looking for matching `"'
bash: line 5: syntax error: unexpected end of file
Here's the solution:
$ jq -r $'.[] | "\(.)" | gsub( "\'" ; "\\\\\'" ) | "echo $\'\(.)\'" ' jsonfile | bash
{"foo":"bar'baz:foo*","bar*":"baz*","etc":"etc"}
{"foo2":"bar2:baz2:foo2*","bar2*":"baz2*","etc":"etc"}
{"foo3":"bar3:baz3:foo3*","bar3*":"baz3*","etc":"etc"}
{"foo4":"bar4:baz4:foo4*","bar4*":"baz4*","etc":"etc"}
Above I am using $'' to quote the jq script. This allows me to escape single quotes using '. I've also changed the curl command to echo so I can test the bash script without bothering the folks at http://restful.com/api.
The 'trick' is to make sure that the bash script we generate also escapes all single quotes with a backslash . So, we have to change ' to \'. That's what gsub is doing.
gsub( "\'" ; "\\\\\'" )
After making that substitution ( ' --> \' ) we pipe the entire string to this:
"echo $\'\(.)\'"
which surrounds the output of gsub with echo $''. Now we are using $' again so the \' is properly understood by bash.
So we wind up with this when we put the curl back in:
jq -r $'.[] | "\(.)" | gsub( "\'" ; "\\\\\'" ) | "curl -d $\'\(.)\' http://restful.com/api " ' jsonfile | bash
Use jq command. This is just example parsing.
for k in $(jq -c '.[]' a.txt); do
echo "hello-" $k
done
Output:
hello- {"foo":"bar:baz:foo*","bar*":"baz*","etc":"etc"}
hello- {"foo2":"bar2:baz2:foo2*","bar2*":"baz2*","etc":"etc"}
hello- {"foo3":"bar3:baz3:foo3*","bar3*":"baz3*","etc":"etc"}
hello- {"foo4":"bar4:baz4:foo4*","bar4*":"baz4*","etc":"etc"}
You can use the $k anywhere inside the loop you want.
for k in $(jq -c '.[]' a.txt); do
curl -d "$k" <url>
done

use curl/bash command in jq

I am trying to get a list of URL after redirection using bash scripting. Say, google.com gets redirected to http://www.google.com with 301 status.
What I have tried is:
json='[{"url":"google.com"},{"url":"microsoft.com"}]'
echo "$json" | jq -r '.[].url' | while read line; do
curl -LSs -o /dev/null -w %{url_effective} $line 2>/dev/null
done
So, is it possible for us to use commands like curl inside jq for processing JSON objects.
I want to add the resulting URL to existing JSON structure like:
[
{
"url": "google.com",
"redirection": "http://www.google.com"
},
{
"url": "microsoft.com",
"redirection": "https://www.microsoft.com"
}
]
Thank you in advance..!
curl is capable of making multiple transfers in a single process, and it can also read command line arguments from a file or stdin, so, you don't need a loop at all, just put that JSON into a file and run this:
jq -r '"-o /dev/null\nurl = \(.[].url)"' file |
curl -sSLK- -w'%{url_effective}\n' |
jq -R 'fromjson | map(. + {redirection: input})' file -
This way only 3 processes will be spawned for the whole task, instead of n + 2 where n is the number of URLs.
I would generate a dictionary with jq per url and slurp those dictionaries into the final list with jq -s:
json='[{"url":"google.com"},{"url":"microsoft.com"}]'
echo "$json" | jq -r '.[].url' | while read url; do
redirect=$(curl -LSs \
-o /dev/null \
-w '%{url_effective}' \
"${url}" 2>/dev/null)
jq --null-input --arg url "${url}" --arg redirect "${redirect}" \
'{url:$url, redirect: $redirect}'
done | jq -s
Alternative (first) solution:
You can output the url and the effective_url as tab separated data and create the output json with jq:
json='[{"url":"google.com"},{"url":"microsoft.com"}]'
echo "$json" | jq -r '.[].url' | while read line; do
prefix="${line}\t"
curl -LSs -o /dev/null -w "${prefix}"'%{url_effective}'"\n" "$line" 2>/dev/null
done | jq -r --raw-input 'split("\t")|{"url":.[0],"redirection":.[1]}'
Both solutions will generate valid json, independently of whatever characters the url/effective_url might contain.
Trying to keep this in JSON all the way is pretty cumbersome. I would simply try to make Bash construct a new valid JSON fragment inside the loop.
So in other words, if $url is the URL and $redirect is where it redirects to, you can do something like
printf '{"url": "%s", "redirection": "%s"}\n' "$url" "$redirect"
to produce JSON output from these strings. So tying it all together
jq -r '.[].url' <<<"$json" |
while read -r url; do
printf '{"url:" "%s", "redirection": "%s"}\n' \
"$url" "$(curl -LSs -o /dev/null -w '%{url_effective}' "$url")"
done |
jq -s
This is still pretty brittle; in particular, if either of the printf input strings could contain a literal double quote, that should properly be escaped.

How to parse JSON in shell script?

I run the curl command $(curl -i -o - --silent -X GET --cert "${CERT}" --key "${KEY}" "$some_url") and save the response in the variable response. ${response} is as shown below
HTTP/1.1 200 OK
Content-Type: application/json; charset=utf-8
Content-Length: 34
Connection: keep-alive
Keep-Alive: timeout=5
X-XSS-Protection: 1;
{"status":"running","details":"0"}
I want to parse the JSON {"status":"running","details":"0"} and assign 'running' and 'details' to two different variables where I can print status and details both. Also if the status is equal to error, the script should exit. I am doing the following to achieve the task -
status1=$(echo "${response}" | awk '/^{.*}$/' | jq -r '.status')
details1=$(echo "${response}" | awk '/^{.*}$/' | jq -r '.details')
echo "Status: ${status1}"
echo "Details: ${details1}"
if [[ $status1 == 'error' ]]; then
exit 1
fi
Instead of parsing the JSON twice, I want to do it only once. Hence I want to combine the following lines but still assign the status and details to two separate variables -
status1=$(echo "${response}" | awk '/^{.*}$/' | jq -r '.status')
details1=$(echo "${response}" | awk '/^{.*}$/' | jq -r '.details')
First, stop using the -i argument to curl. That takes away the need for awk (or any other pruning of the header after-the-fact).
Second:
{
IFS= read -r -d '' status1
IFS= read -r -d '' details1
} < <(jq -r '.status + "\u0000" + .details + "\u0000"' <<<"$response")
The advantage of using a NUL as a delimiter is that it's the sole character that can't be present in the value of a C-style string (which is how shell variables' values are stored).
You can use a construction like:
read status1 details1 < <(jq -r '.status + " " + .details' <<< "${response}")
You use read to assign the different inputs to two variables (or an array, if you want), and use jq to print the data you need separated by whitespace.
As Benjamin already suggested, only retrieving the json is a better way to go. Poshi's solution is solid.
However, if you're looking for the most compact to do this, no need to save the response as a variable if the only thing your're going to do with it is extract other variables from it on a one time basis. Just pipe curl directly into:
curl "whatever" | jq -r '[.status, .details] |#tsv'
or
curl "whatever" | jq -r '[.status, .details] |join("\t")'
and you'll get your values fielded for you.

Selection of multiple json keys using jq

As a newbee to bash and jq, I was trying to download several urls from a json file using jq command in bash scripts.
My items.json file looks like this :
[
{"title" : [bob], "link" :[a.b.c]},
{"title" : [alice], "link" :[d.e.f]},
{"title" : [carol], "link" :[]}
]
what I was initially doing was just filter the non-empty link and put them in an array and then download the array:
#!/bin/bash
lnk=( $(jq -r '.[].link[0] | select (.!=null)' items.json) )
for element in ${lnk[#]}
do
wget $element
done
But the problem of this approach is that all the files downloaded use the link as the file names.
I wish to filter json file but still keeps the title name with the link so that i can rename the file in the wget command. But I dont have any idea on what structure should I use here. So how can i keep the title to in the filter and use it after?
You can use this:
IFS=$'\n' read -d '' -a titles < <(jq -r '.[] | select (.link[0]!=null) | .title[0]' items.json);
IFS=$'\n' read -d '' -a links < <(jq -r '.[] | select (.link[0]!=null) | .link[0]' items.json);
Then you can iterate over arrays "${title[#]}" & ${links[#]}...
for i in ${!titles[#]}; do
wget -O "${titles[i]}" "${links[#]}"
done
EDIT: Easier & safer approach:
jq -r '.[] | select (.link[0]!=null) | #sh "wget -O \(.title[0]) \(.link[0])"' items.json | bash
Here is a bash script demonstrating reading the result of a jq filter into bash variables.
#!/bin/bash
jq -M -r '
.[]
| select(.link[0]!=null)
| .title[0], .link[0]
' items.json | \
while read -r title; read -r url; do
echo "$title: $url" # replace with wget command
done

Get JSON value from URL in BASH

I need to get the "snapshot" value at the top of the file from this url: https://s3.amazonaws.com/Minecraft.Download/versions/versions.json
So I should get a variable that contains "14w08a" when I run the command to parse the json.
This will do the trick
$ curl -s "$url" | grep -Pom 1 '"snapshot": "\K[^"]*'
14w08a
best thing to do is use a tool with a JSON parser. For example:
value=$(
curl -s "$url" |
ruby -rjson -e 'data = JSON.parse(STDIN.read); puts data["latest"]["snapshot"]'
)