70 lines
1.9 KiB
ReStructuredText
70 lines
1.9 KiB
ReStructuredText
Using JSON
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==========
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Modify JSON by Using Shell Commands
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-----------------------------------
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.. note::
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Nowadays Web services are `JSON`-based, so making your script `JSON` aware is
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probably a good choice. In order to be able to extract data from a `JSON`
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document as well as composing `JSON` documents from a script, you can leverage
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`jq <https://stedolan.github.io/jq/>`_.
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Example #1
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++++++++++
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In this example our *Kapow!* service will receive a `JSON` value with an incorrect
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date, then our ``pow`` file will fix it and return the correct value to the user.
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.. code-block:: console
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:linenos:
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$ cat fix_date.pow
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kapow route add -X POST /fix-date - <<-'EOF'
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kapow set /response/headers/Content-Type application/json
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kapow get /request/body | jq --arg newdate "$(date +'%Y-%m-%d_%H-%M-%S')" '.incorrectDate=$newdate' | kapow set /response/body
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EOF
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Call the service with :program:`curl`:
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.. code-block:: console
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:linenos:
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$ curl -X POST http://localhost:8080/fix-date -H 'Content-Type: application/json' -d '{"incorrectDate": "no way, Jose"}'
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{
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"incorrectDate": "2019-11-22_10-42-06"
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}
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Example #2
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++++++++++
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In this example we extract the ``name`` field from the incoming `JSON` document in
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order to generate a two-attribute `JSON` response.
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.. code-block:: console
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$ cat echo-attribute.pow
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kapow route add -X POST /echo-attribute - <<-'EOF'
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JSON_WHO=$(kapow get /request/body | jq -r .name)
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kapow set /response/headers/Content-Type application/json
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kapow set /response/status 200
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jq --arg greet Hello --arg value "${JSON_WHO:-World}" --null-input '{ greet: $greet, to: $value }' | kapow set /response/body
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EOF
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Call the service with :program:`curl`:
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.. code-block:: console
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:linenos:
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:emphasize-lines: 4
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$ curl -X POST http://localhost:8080/echo-attribute -H 'Content-Type: application/json' -d '{"name": "MyName"}'
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{
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"greet": "Hello",
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"to": "MyName"
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}
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