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Retrieve POST Parameters ​

When a cloud function is called using a POST request, the HTTP Request Body is converted into params variables in the corresponding function, making it easily accessible and usable by developers.

Depending on the request Content Type, params will also have different types.

application/json ​

application/json is the most common request data type, where params is of type Object and represents the Request Body processed by JSON.parse.

For example, for the following cloud function:

js
module.exports = async function(params, context) {
  return {
    method: context.method,
    paramsFromPost: params
  };
}

module.exports = async function(params, context) {
  return {
    method: context.method,
    paramsFromPost: params
  };
}

After deployment, send a POST request with data of type application/json:

sh
curl -X POST -d '{"hello": "world"}' -H "Content-Type:application/json" \
https://sample.hk.aircode.run/postParams

curl -X POST -d '{"hello": "world"}' -H "Content-Type:application/json" \
https://sample.hk.aircode.run/postParams

Will get the following response:

json
{ 
  "method": "POST",
  "paramsFromPost": {
    "hello": "world"
  }
}

{ 
  "method": "POST",
  "paramsFromPost": {
    "hello": "world"
  }
}

multipart/form-data ​

multipart/form-data is generally used for uploading files, where params is of type Object and represents the Request Body in the form of Key-Value pairs.

Each file contains the following information:

typescript
type UploadFile = {
  name: string;       // Name of the uploaded file
  type: string;       // Mime type of the file
  size: number;       // Size of the file in bytes
  buffer: Buffer;     // Content of the entire file
}

type UploadFile = {
  name: string;       // Name of the uploaded file
  type: string;       // Mime type of the file
  size: number;       // Size of the file in bytes
  buffer: Buffer;     // Content of the entire file
}

For example, for the following cloud function:

js
module.exports = async function(params, context) {
  return {
    method: context.method,
    paramsFromPost: params
  };
}

module.exports = async function(params, context) {
  return {
    method: context.method,
    paramsFromPost: params
  };
}

After deployment, send a POST request with data of type multipart/form-data:

sh
# Please make sure you have hello.txt in your directory
curl -X POST -F "abc=123" -F xyz=@hello.txt \
https://sample.hk.aircode.run/postParams

# Please make sure you have hello.txt in your directory
curl -X POST -F "abc=123" -F xyz=@hello.txt \
https://sample.hk.aircode.run/postParams

Will get the following response:

json
{
  "method": "POST",
  "paramsFromPost": {
    "abc": "123",
    "xyz": {
      "name": "hello.txt",
      "type": "text/plain",
      "size": 11,
      "buffer": {
        "type": "Buffer",
        "data": [ 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100 ]
      }
    }
  }
}

{
  "method": "POST",
  "paramsFromPost": {
    "abc": "123",
    "xyz": {
      "name": "hello.txt",
      "type": "text/plain",
      "size": 11,
      "buffer": {
        "type": "Buffer",
        "data": [ 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100 ]
      }
    }
  }
}

Tips

If you want to learn more about how to upload files from your browser and save them to AirCode's File Storage, you can refer to the guide: Upload Files - Upload in a Browser.

application/x-www-form-urlencoded ​

When the Content Type of the request is application/x-www-form-urlencoded, the type of params is Object, and its value represents the Request Body processed by querystring.parse.

Tips

When using application/x-www-form-urlencoded, all values are of type string or Array<string>, i.e., params.a === '1' when passed a=1.

For example, for the following cloud function:

js
module.exports = async function(params, context) {
  return {
    method: context.method,
    paramsFromPost: params
  };
}

module.exports = async function(params, context) {
  return {
    method: context.method,
    paramsFromPost: params
  };
}

After deployment, send a POST request with data of type application/x-www-form-urlencoded:

sh
curl -X POST -d 'hello=world&abc=xyz&abc=123' \
-H "Content-Type:application/x-www-form-urlencoded" \
https://sample.hk.aircode.run/postParams

curl -X POST -d 'hello=world&abc=xyz&abc=123' \
-H "Content-Type:application/x-www-form-urlencoded" \
https://sample.hk.aircode.run/postParams

Will get the following response:

json
{
  "method": "POST",
  "paramsFromPost": {
    "hello": "world",
    "abc": [ "xyz", "123" ]
  }
}

{
  "method": "POST",
  "paramsFromPost": {
    "hello": "world",
    "abc": [ "xyz", "123" ]
  }
}

text/plain ​

text/plain is generally used to send plain text content, where params is of type string, representing the content of that text.

For example, for the following cloud function:

js
module.exports = async function(params, context) {
  return {
    method: context.method,
    paramsFromPost: params
  };
}

module.exports = async function(params, context) {
  return {
    method: context.method,
    paramsFromPost: params
  };
}

After deployment, send a POST request with data of type text/plain:

sh
curl -X POST -d "Some Text..." -H "Content-Type:text/plain" \
https://sample.hk.aircode.run/postParams

curl -X POST -d "Some Text..." -H "Content-Type:text/plain" \
https://sample.hk.aircode.run/postParams

will get the following response.

json
{
  "method": "POST",
  "paramsFromPost": "Some Text..."
}

{
  "method": "POST",
  "paramsFromPost": "Some Text..."
}

Other Content Types ​

When using other content types (e.g. application/octet-stream), the type of params is Buffer and represents the raw binary data of the request.

For example, for the following cloud functions:

js
module.exports = async function(params, context) {
  return {
    method: context.method,
    paramsFromPost: params
  };
}

module.exports = async function(params, context) {
  return {
    method: context.method,
    paramsFromPost: params
  };
}

After deployment, send a POST request with data of type application/octet-stream:

sh
curl -X POST -d "Hello World" -H "Content-Type:application/octet-stream" \
https://sample.hk.aircode.run/postParams

curl -X POST -d "Hello World" -H "Content-Type:application/octet-stream" \
https://sample.hk.aircode.run/postParams

Will get the following response:

json
{
  "method": "POST",
  "paramsFromPost": {
    "type": "Buffer",
    "data": [ 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100 ]
  }
}

{
  "method": "POST",
  "paramsFromPost": {
    "type": "Buffer",
    "data": [ 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100 ]
  }
}