I would like to get the values from Json file. Which is working.
JsonFileToTest:
{
"permissions": [
{
"emailid": "test1#test.com",
"rights": "read"
},
{
"emailid": "test2#test.com",
"rights": "read"
}
]
}
readPermissions=($(jq -r '.permissions' JsonFileToTest))
# The command below works perfectly, But when I Put it in a loop, It does not.
#echo ${readPermissions[#]} | jq 'values[].emailid'
for vals in ${readPermissions[#]}
do
# I would like o extract the email id of the user. The loop is not working atm.
echo ${vals[#]} | jq 'values[].emailid'
done
what am I missing here?
thanks
If you really want to do it this way, that might look like:
readarray -t permissions < <(jq -c '.permissions[]' JsonFileToTest)
for permissionSet in "${permissions[#]}"; do
jq -r '.emailid' <<<"$permissionSet"
done
Note that we're telling jq to print one line per item (with -c), and using readarray -t to read each line into an array element (unlike the array=( $(...command...) ) antipattern, which splits not just on newlines but on other whitespace as well, and expands globs in the process).
But there's no reason whatsoever to do any of that. You'll get the exact same result simply running:
jq -r '.permissions[].emailid' JsonFileToTest
Related
I have a JSON data as follows in data.json file
[
{"original_name":"pdf_convert","changed_name":"pdf_convert_1"},
{"original_name":"video_encode","changed_name":"video_encode_1"},
{"original_name":"video_transcode","changed_name":"video_transcode_1"}
]
I want to iterate through the array and extract the value for each element in a loop. I saw jq. I find it difficult to use it to iterate. How can I do that?
Just use a filter that would return each item in the array. Then loop over the results, just make sure you use the compact output option (-c) so each result is put on a single line and is treated as one item in the loop.
jq -c '.[]' input.json | while read i; do
# do stuff with $i
done
By leveraging the power of Bash arrays, you can do something like:
# read each item in the JSON array to an item in the Bash array
readarray -t my_array < <(jq --compact-output '.[]' input.json)
# iterate through the Bash array
for item in "${my_array[#]}"; do
original_name=$(jq --raw-output '.original_name' <<< "$item")
changed_name=$(jq --raw-output '.changed_name' <<< "$item")
# do your stuff
done
jq has a shell formatting option: #sh.
You can use the following to format your json data as shell parameters:
cat data.json | jq '. | map([.original_name, .changed_name])' | jq #sh
The output will look like:
"'pdf_convert' 'pdf_convert_1'"
"'video_encode' 'video_encode_1'",
"'video_transcode' 'video_transcode_1'"
To process each row, we need to do a couple of things:
Set the bash for-loop to read the entire row, rather than stopping at the first space (default behavior).
Strip the enclosing double-quotes off of each row, so each value can be passed as a parameter to the function which processes each row.
To read the entire row on each iteration of the bash for-loop, set the IFS variable, as described in this answer.
To strip off the double-quotes, we'll run it through the bash shell interpreter using xargs:
stripped=$(echo $original | xargs echo)
Putting it all together, we have:
#!/bin/bash
function processRow() {
original_name=$1
changed_name=$2
# TODO
}
IFS=$'\n' # Each iteration of the for loop should read until we find an end-of-line
for row in $(cat data.json | jq '. | map([.original_name, .changed_name])' | jq #sh)
do
# Run the row through the shell interpreter to remove enclosing double-quotes
stripped=$(echo $row | xargs echo)
# Call our function to process the row
# eval must be used to interpret the spaces in $stripped as separating arguments
eval processRow $stripped
done
unset IFS # Return IFS to its original value
From Iterate over json array of dates in bash (has whitespace)
items=$(echo "$JSON_Content" | jq -c -r '.[]')
for item in ${items[#]}; do
echo $item
# whatever you are trying to do ...
done
Try Build it around this example. (Source: Original Site)
Example:
jq '[foreach .[] as $item ([[],[]]; if $item == null then [[],.[0]] else [(.[0] + [$item]),[]] end; if $item == null then .[1] else empty end)]'
Input [1,2,3,4,null,"a","b",null]
Output [[1,2,3,4],["a","b"]]
None of the answers here worked for me, out-of-the-box.
What did work was a combination of a few:
projectList=$(echo "$projRes" | jq -c '.projects[]')
IFS=$'\n' # Read till newline
for project in ${projectList[#]}; do
projectId=$(jq '.id' <<< "$project")
projectName=$(jq -r '.name' <<< "$project")
...
done
unset IFS
NOTE: I'm not using the same data as the question does, in this example assume projRes is the output from an API that gives us a JSON list of projects, eg:
{
"projects": [
{"id":1,"name":"Project"},
... // array of projects
]
}
An earlier answer in this thread suggested using jq's foreach, but that may be much more complicated than needed, especially given the stated task. Specifically, foreach (and reduce) are intended for certain cases where you need to accumulate results.
In many cases (including some cases where eventually a reduction step is necessary), it's better to use .[] or map(_). The latter is just another way of writing [.[] | _] so if you are going to use jq, it's really useful to understand that .[] simply creates a stream of values.
For example, [1,2,3] | .[] produces a stream of the three values.
To take a simple map-reduce example, suppose you want to find the maximum length of an array of strings. One solution would be [ .[] | length] | max.
Here is a simple example that works in zch shell:
DOMAINS='["google","amazon"]'
arr=$(echo $DOMAINS | jq -c '.[]')
for d in $arr; do
printf "Here is your domain: ${d}\n"
done
I stopped using jq and started using jp, since JMESpath is the same language as used by the --query argument of my cloud service and I find it difficult to juggle both languages at once. You can quickly learn the basics of JMESpath expressions here: https://jmespath.org/tutorial.html
Since you didn't specifically ask for a jq answer but instead, an approach to iterating JSON in bash, I think it's an appropriate answer.
Style points:
I use backticks and those have fallen out of fashion. You can substitute with another command substitution operator.
I use cat to pipe the input contents into the command. Yes, you can also specify the filename as a parameter, but I find this distracting because it breaks my left-to-right reading of the sequence of operations. Of course you can update this from my style to yours.
set -u has no function in this solution, but is important if you are fiddling with bash to get something to work. The command forces you to declare variables and therefore doesn't allow you to misspell a variable name.
Here's how I do it:
#!/bin/bash
set -u
# exploit the JMESpath length() function to get a count of list elements to iterate
export COUNT=`cat data.json | jp "length( [*] )"`
# The `seq` command produces the sequence `0 1 2` for our indexes
# The $(( )) operator in bash produces an arithmetic result ($COUNT minus one)
for i in `seq 0 $((COUNT - 1))` ; do
# The list elements in JMESpath are zero-indexed
echo "Here is element $i:"
cat data.json | jp "[$i]"
# Add or replace whatever operation you like here.
done
Now, it would also be a common use case to pull the original JSON data from an online API and not from a local file. In that case, I use a slightly modified technique of caching the full result in a variable:
#!/bin/bash
set -u
# cache the JSON content in a stack variable, downloading it only once
export DATA=`api --profile foo compute instance list --query "bar"`
export COUNT=`echo "$DATA" | jp "length( [*] )"`
for i in `seq 0 $((COUNT - 1))` ; do
echo "Here is element $i:"
echo "$DATA" | jp "[$i]"
done
This second example has the added benefit that if the data is changing rapidly, you are guaranteed to have a consistent count between the elements you are iterating through, and the elements in the iterated data.
This is what I have done so far
arr=$(echo "$array" | jq -c -r '.[]')
for item in ${arr[#]}; do
original_name=$(echo $item | jq -r '.original_name')
changed_name=$(echo $item | jq -r '.changed_name')
echo $original_name $changed_name
done
I want to merge some json in a file with some json generated at runtime. jq seems to have no difficulty if all the files passed to it are here-strings, or files in the system. But if I try to mix the file types it seems the here-strings are ignored, see snippet below:
Two normal files:
bash-4.2# echo '{"key":0}' > zero
bash-4.2# echo '{"key":1}' > one
bash-4.2# jq --slurp add zero one
{
"key": 1
}
Normal file and here-string (only normal file appears in result!):
bash-4.2# jq --slurp add zero <<< '{"key":1}'
{
"key": 0
}
Here-string first, then normal file (only normal file appears in result!):
bash-4.2# jq --slurp add <<< '{"key":0,"anotherkey":2}' one
{
"key": 1
}
Single here-string (works fine):
bash-4.2# jq --slurp add <<< '{"key":0}'
{
"key": 0
}
Two here-strings (works fine): EDIT: Output is misleading, something else is going on here.
bash-4.2# jq --slurp add <<< '{"key":0}' <<< '{"key":1}'
{
"key": 1
}
My suspicion is that jq works just fine and I am ignorant of how bash resolves the here-strings. But, how would I debug this to improve my understanding?
Note: A very easy workaround would be to evaluate my runtime json and produce a file, then merge the two files as above. I really want to know why the bold examples above don't produce what I would expect.
After reading through the comments this is my understanding:
<<< is evaluated by the shell first and redirects stdin. If jq receives no positional arguments after the filter, it reads from stdin. Therefore all these statements are equivalent:
echo "{}" | jq --slurp add
<<< {} jq --slurp add
jq <<< {} --slurp add
jq --slurp <<< {} add
jq --slurp add <<< {}
If jq does receive positional arguments after the filter, it interprets them as filenames. It adheres to the convention of treating - as stdin.
bash-4.2# echo '{"one":1,"two":1}' > first
bash-4.2# echo '{"three":3}' > third
bash-4.2# jq --slurp add first - third <<< '{"two":2}'
{
"one": 1,
"two": 2,
"three": 3
}
The here-string construct simply redirects standard input. You will separately need to tell jq to read standard input if you call it in a way where it receives file name arguments. The de facto standard way to do that is to specify - as the input (pseudo-) filename.
I believe one of your test cases didn't actually work, and just looked like it did because the input data was constructed so as to be a no-op.
One idea would be to use process substitution which, in essence, provides jq with a (temp) file descriptor it can work with.
Using awk to demonstrate the file descriptor idea:
$ awk '{print FILENAME}' <(echo 'abc')
/dev/fd/63
Demonstrating with a few of your examples:
$ jq --slurp add zero <(echo '{"key":1}')
{
"key": 1
}
$ jq --slurp add zero <(echo '{"keyx":1}')
{
"key": 0,
"keyx": 1
}
$ jq --slurp add <(echo '{"key":0,"anotherkey":2}') one
{
"key": 1,
"anotherkey": 2
}
$ jq --slurp add <(echo '{"key":0}') <(echo '{"key":1}')
{
"key": 1
}
$ jq --slurp add <(echo '{"key":0}') <(echo '{"keyx":1}')
{
"key": 0,
"keyx": 1
}
So, I am getting a response from an API that I am calling in a shell script in the following form
[{"id":100000004,"name":"Customs Clearance Requested"},{"id":100000005,"name":"Customs Cleared"},{"id":100000006,"name":"Cargo Loaded to Vessel"}]
I want to create a map out of it that will help me lookup the id's from a name and use it in the shell script. So something like map["Customs Clearance Requested"] would give me 100000004 which I can use further. Can this be done using jq? I am pretty new to shell scripting and jq and got stuck with above thing
json='[{"id":100000004,"name":"Customs Clearance Requested"},{"id":100000005,"name":"Customs Cleared"},{"id":100000006,"name":"Cargo Loaded to Vessel"}]'
declare -A map
while IFS= read -r -d '' name && IFS= read -r -d '' value; do
map[$name]=$value
done < <(jq -j '.[] | "\(.name)\u0000\(.id)\u0000"' <<<"$json")
declare -p map # demo purposes: print the map we created as output
...emits as output:
declare -A map=(["Cargo Loaded to Vessel"]="100000006" ["Customs Clearance Requested"]="100000004" ["Customs Cleared"]="100000005" )
...which you can query exactly as requested:
$ echo "${map['Cargo Loaded to Vessel']}"
100000006
You could use the select function, e.g.:
data='[{"id":100000004,"name":"Customs Clearance Requested"},{"id":100000005,"name":"Customs Cleared"},{"id":100000006,"name":"Cargo Loaded to Vessel"}]'
jq 'map(select(.["name"] == "Customs Clearance Requested"))' <<< $data
It will get all elements which name equals "Customs Clearance Requested", e.g.:
[
{
"id": 100000004,
"name": "Customs Clearance Requested"
}
]
If you want to get the id field:
jq 'map(select(.["name"] == "Customs Clearance Requested")["id"])' <<< $data
This will output:
[
100000004
]
Please note that it will return an array and not a single element because the search does not know how many results will be found.
If you want to generalize this in a shell function, you could write:
function get_id_from_name
{
# $1=name to search for
local filter=$(printf 'map(select(.["name"] == "%s")["id"])' "$1")
jq "$filter"
}
Then call it like that:
get_id_from_name "Customs Clearance Requested" <<< $data
If your data is stored in a file, you could call it this way:
get_id_from_name "Customs Clearance Requested" < /path/to/file.json
The following is very similar to #CharlesDuffy's excellent answer but does not assume that the .name and .id values are NUL-free (i.e., do not have any "\u0000" characters):
declare -A map
while read -r name
do
name=$(sed -e 's/^"//' -e 's/"$//' <<< "$name")
read -r id
map[$name]="$id"
done < <(echo "$json" | jq -c '.[]|.name,.id')
The point is that the -j option is like -r (i.e., produces "raw output"), whereas the -c option produces JSON.
This means that if you don't want the .id values as JSON strings, then the above won't be a solution; also, if the .name values contain double-quotes, then you might want to deal with the occurrences of \".
I have created a simple script to store response from a third party API
The request is like this..
https://externalservice.io/orders?key=password&records=50&offset=0
The response is as follows:
{
"results": [
{
"engagement": {
"id": 29090716,
"portalId": 62515,
"active": true,
"createdAt": 1444223400781,
"lastUpdated": 1444223400781,
"createdBy": 215482,
"modifiedBy": 215482,
"ownerId": 70,
"type": "NOTE",
"timestamp": 1444223400781
},
},
],
"hasMore": true,
"offset": 4623406
}
If there is a hasMore attribute, I need to read the offset value to get the next set of records.
Right now I've created a script that simply loops over the estimated number of records (I believed there is) and thought incrementing the offset would work but this is not the case as the offset is not incremental.
#!/bin/bash
for i in {1..100}; do
curl -s "https://externalservice.io/orders?key=password&records=50&offset=$i" >>outfile.txt 2>&1
done
Can someone explain how I can read continue the script reading the offset value until hasMore=false?
You can read a value from a json using the jq utility:
$ jq -r ".hasMore" outfile
true
Here is what you could use:
more="true"
offset=0
while [ $more = "true" ]; do
echo $offset
response=$(curl -s "https://example.com/orders?offset=$offset")
more=$(echo $response | tr '\r\n' ' ' | jq -r ".hasMore")
offset=$(echo $response | tr '\r\n' ' ' | jq -r ".offset")
done
You can use jq utility to extract specific attribute from you json response:
$ jq -r ".hasMore" outfile
true
jq expects perfectly valid json input, otherwise it will print error.
Most common mistake is to echo json stored in variable. A mistake, because echo will interpret all escaped newlines in your json and will send unescaped newlines within values causing jq to throw parse error: Invalid string: control characters from U+0000 through U+001F must be escaped at line message.
To avoid modification to json (and avoiding an error) we need to use printf instead of echo.
Here is the solution without breaking json content:
more="true"
offset=0
while [ $more = "true" ]; do
echo $offset
response=$(curl -s "https://example.com/orders?offset=$offset")
more=$(printf "%s\n" "$response" | jq -r ".hasMore")
offset=$(printf "%s\n" "$response" | jq -r ".offset")
done
I would like to convert a list into JSON array. I'm looking at jq for this but the examples are mostly about parsing JSON (not creating it). It would be nice to know proper escaping will occur. My list is single line elements so the new line will probably be the best delimiter.
I was also trying to convert a bunch of lines into a JSON array, and was at a standstill until I realized that -s was the only way I could handle more than one line at a time in the jq expression, even if that meant I'd have to parse the newlines manually.
jq -R -s -c 'split("\n")' < just_lines.txt
-R to read raw input
-s to read all input as a single string
-c to not pretty print the output
Easy peasy.
Edit: I'm on jq ≥ 1.4, which is apparently when the split built-in was introduced.
--raw-input, then --slurp
Just summarizing what the others have said in a hopefully quicker to understand form:
cat /etc/hosts | jq --raw-input . | jq --slurp .
will return you:
[
"fe00::0 ip6-localnet",
"ff00::0 ip6-mcastprefix",
"ff02::1 ip6-allnodes",
"ff02::2 ip6-allrouters"
]
Explanation
--raw-input/-R:
Don´t parse the input as JSON. Instead, each line of text is passed
to the filter as a string. If combined with --slurp, then the
entire input is passed to the filter as a single long string.
--slurp/-s:
Instead of running the filter for each JSON object in the input,
read the entire input stream into a large array and run the filter
just once.
You can also use jq -R . to format each line as a JSON string and then jq -s (--slurp) to create an array for the input lines after parsing them as JSON:
$ printf %s\\n aa bb|jq -R .|jq -s .
[
"aa",
"bb"
]
The method in chbrown's answer adds an empty element to the end if the input ends with a linefeed, but you can use printf %s "$(cat)" to remove trailing linefeeds:
$ printf %s\\n aa bb|jq -R -s 'split("\n")'
[
"aa",
"bb",
""
]
$ printf %s\\n aa bb|printf %s "$(cat)"|jq -R -s 'split("\n")'
[
"aa",
"bb"
]
If the input lines don't contain ASCII control characters (which have to be escaped in strings in valid JSON), you can use sed:
$ printf %s\\n aa bb|sed 's/["\]/\\&/g;s/.*/"&"/;1s/^/[/;$s/$/]/;$!s/$/,/'
["aa",
"bb"]
Update: If your jq has inputs you can simply write:
jq -nR [inputs] /etc/hosts
to produce a JSON array of strings. This avoids having to read the text file as a whole.
I found in the man page for jq and through experimentation what seems to me to be a simpler answer.
$ cat test_file.txt | jq -Rsc '. / "\n" - [""]'
["aa","bb"]
The -R is to read without trying to parse json, the -s says to read all of the input as one string, and the -c is for one-line output - not necessary, but it's what I was looking for.
Then in the string I pass to jq, the '.' says take the input as it is. The '/ \n' says to divide the string (split it) on newlines. The '- [""]' says to remove from the resulting array any empty strings (resulting from an extra newline at the end).
It's one line and without any complicated constructs, using just simple built in jq features.