`processors`

Getting Request Data

Overview

Learn

Overview

Dynamic URLs

`processors`

Getting Request Data

Fetching Data Using `http`

Getting Request Data

`request-data` processor can be used to find the data from the HTTP request. Query string and [named-path parameters](/dynamic-urls/) or from request body.

Reading Individual Fields

Say the request was:

curl 'http://127.0.0.1:8000/test/?message=hello%20world'

Lang:

And you wanted to extract the value of `message`, you can do it like this:

-- import: fastn/processors as pr

-- string message:
$processor$: pr.request-data

-- ds.markdown: $message

Lang:

ftd

Note that the field must be present or else this will give an error.

Using Default Value As Fallback

If you expect the message to be optional, maybe the user made a request like this:

curl 'http://127.0.0.1:8000/test/'

Lang:

without passing `message`, the earlier code will return HTTP 500 Error ([this is a bug, should return 404](https://github.com/fastn-stack/fastn/issues/1103)), one way to avoid that is to specify a default value:

-- import: fastn/processors as pr

-- string message: hello
$processor$: pr.request-data

-- ds.markdown: $message

Lang:

ftd

In this case we have provided a default value of `hello`, so if `message` is not found the HTTP request, the variable `message` be assiged the default value, `hello`.

Reading Multiple Bits In One Go

You can use a record to read multiple data from request.

curl 'http://127.0.0.1:8000/test/?message=hello%20world&flag=true'

Lang:

In above example url contains query parameter `message` with value `hello world` and `flag` with value `true`. We can access them `ftd` file by using `request-data` processor.

-- import: fastn/processors as pr

-- record r-data:
string message: default value of message
boolean flag:

-- r-data data:
$processor$: pr.request-data

-- ds.markdown: $data.message

Lang:

ftd

Please note that all the parameters defined in the record must be present, or they must have a default value.

Key Values In Dynamic URLs And Sitemap

When using [dynamic URLs](/dynamic-urls/) or the [sitemap](/understanding-sitemap/-/build/), the key value parameters can also be extracted using the same method:

-- fastn.dynamic-urls:

# RD Test:
url: /rd-test//
document: ftd-host/r.ftd
flag: false

Lang:

ftd

Here we have specified `flag: false` in the dynamic URL configuration, and it will be picked up.

JSON Body

If the request body is not empty, and has content type `application/json`, the body is parsed as JSON and the fields in your record are looked in the JSON as well.

Note On Priority

If a field is present in more than one places, this is the order of preference: - data in `FASTN.ftd` is highest priority - then comes data in JSON body - then the data in the named parameter - and finally the GET query parameter is lowest priorty

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[💻️](/community/)

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