@cerebral/http

install

NPM

npm install @cerebral/http

description

The HTTP provider exposes the ability to do HTTP requests both in actions and directly in signals. It supports cors and file upload, with progress handling. It default to json, but you can configure it to whatever you want.

Read more about http in the Cerebral in depth - Http article.

import {set} from 'cerebral/operators'
import {httpGet} from '@cerebral/http/operators'
import {state, props, string} from 'cerebral/tags'

export default [
  httpGet(string`/items/${props`itemKey`}`),
  set(state`app.currentItem`, props`result`)
]

All factories of HTTP provider supports template tags.

instantiate

import {Controller} from 'cerebral'
import HttpProvider from '@cerebral/http'

const controller = Controller({
  providers: [
    HttpProvider({
      // Prefix all requests with this url
      baseUrl: 'https://api.github.com',

      // Any default headers to pass on requests
      headers: {
        'Content-Type': 'application/json; charset=UTF-8',
        'Accept': 'application/json'
      },

      // When talking to cross origin (cors), pass cookies
      // if set to true
      withCredentials: false
    })
  ]
})

You can update these default options in an action:

function updateDefaultHttpOptions({http}) {
  http.updateOptions({
    // Updated options
  })
}

error

HttpProviderError

import {HttpProviderError} from '@cerebral/http'

// Error structure
{
  name: 'HttpProviderError',
  message: 'Some potential error message',
  body: 'Message or response body',
  status: 200,
  isAborted: false,
  headers: {},
  stack: '...'  
}

request

function someGetAction ({http}) {
  return http.request({
    // Any http method
    method: 'GET',

    // Url you want to request to
    url: '/items'

    // Request body as object. Will automatically be stringified if json and
    // urlEncoded if application/x-www-form-urlencoded
    body: {},

    // Query as object, will automatically be urlEncoded
    query: {},

    // If cross origin request, pass cookies
    withCredentials: false,

    // Any additional http headers, or overwrite default
    headers: {},

    // A function or signal path (foo.bar.requestProgressed) that
    // triggers on request progress. Passes {progress: 45} etc.
    onProgress: null
  })
}

get

action

function someGetAction ({http}) {
  return http.get('/items', {
    // QUERY object
  }, {
    // Any options defined in "Custom request"
  })
}

factory

import {httpGet} from '@cerebral/http/operators'

export default [
  httpGet('/items'),

  // Alternatively with explicit paths
  httpGet('/items'), {
    success: [],
    error: [],
    abort: [], // Optional
    [STATUS_CODE]: [] // Optionally any status code, ex. 404: []
  }
]

output

{
  result: 'the response',
  status: 200,

  // If aborted
  isAborted: true
}

post

action

function somePostAction ({http}) {
  return http.post('/items', {
    // BODY object
  }, {
    // Any options defined in "Custom request"
  })
}

factory

import {httpPost} from '@cerebral/http/operators'
import {props} from 'cerebral/tags'

export default [
  httpPost('/items', {
    title: props`itemTitle`,
    foo: 'bar'
  }),

  // Alternatively with explicit paths
  httpPost('/items', {
    title: props`itemTitle`,
    foo: 'bar'
  }), {
    success: [],
    error: [],
    abort: [], // Optional
    [STATUS_CODE]: [] // Optionally any status code, ex. 404: []
  }
]

output

{
  result: 'the response',
  status: 200,

  // If aborted
  isAborted: true
}

put

action

function somePutAction ({http}) {
  return http.put('/items/1', {
    // BODY object
  }, {
    // Any options defined in "Custom request"
  })
}

factory

import {httpPost} from '@cerebral/http/operators'

export default [
  httpPut('/items', {
    // BODY object
  }),

  // Alternatively with explicit paths
  httpPut('/items', {
    // BODY object
  }), {
    success: [],
    error: [],
    abort: [], // Optional
    [STATUS_CODE]: [] // Optionally any status code, ex. 404: []
  }
]

output

{
  result: 'the response',
  status: 200,

  // If aborted
  isAborted: true
}

patch

action

function somePatchAction ({http}) {
  return http.patch('/items/1', {
    // BODY object
  }, {
    // Any options defined in "Custom request"
  })
}

factory

import {httpPatch} from '@cerebral/http/operators'
import {state, props, string} from 'cerebral/tags'

export default [
  httpPatch(string`/items/${props`itemId`}`, state`patchData`),

  // Alternatively with explicit paths
  httpPatch(string`/items/${props`itemId`}`, state`patchData`), {
    success: [],
    error: [],
    abort: [], // Optional
    [STATUS_CODE]: [] // Optionally any status code, ex. 404: []
  }
]

output

{
  result: 'the response',
  status: 200,

  // If aborted
  isAborted: true
}

delete

action

function someDeleteAction ({http}) {
  return http.delete('/items/1', {
    // QUERY object
  }, {
    // Any options defined in "Custom request"
  })
}

factory

import {httpPost} from '@cerebral/http/operators'
import {state} from 'cerebral/tags'

export default [
  httpDelete(string`/items/${state`currentItemId`}`),

  // Alternatively with explicit paths
  httpDelete(string`/items/${state`currentItemId`}`), {
    success: [],
    error: [],
    abort: [], // Optional
    [STATUS_CODE]: [] // Optionally any status code, ex. 404: []
  }
]

output

{
  result: 'the response',
  status: 200,

  // If aborted
  isAborted: true
}

uploadFile

action

function someDeleteAction ({http, props}) {
  return http.uploadFile('/upload', props.files, {
    name: 'filename.png', // Default to "files"
    data: {}, // Additional form data
    headers: {},
    onProgress: 'some.signal.path' // Upload progress
  })
}

factory

import {httpUploadFile} from '@cerebral/http/operators'
import {state, props} from 'cerebral/tags'

export default [
  httpUploadFile('/uploads', props`file`, {
    name: state`currentFileName`
  }),

  // Alternatively with explicit paths
  httpUploadFile('/uploads', props`file`, {
    name: state`currentFileName`,
    onProgress: 'some.signal.path'
  }), {
    success: [],
    error: [],
    abort: [], // Optional
    [STATUS_CODE]: [] // Optionally any status code, ex. 404: []
  }
]

output

{
  result: 'the response',
  status: 200,

  // If aborted
  isAborted: true
}

abort

You can abort any running request, causing the request to resolve as status code 0 and set an isAborted property on the response object. The string is a regexp string.

action

function abortRequest({http}) {
  http.abort('/items*')
}

factory

import {httpAbort} from '@cerebral/http/operators'

export default [
  httpAbort('/items*') // also supports tags
]

response

function someGetAction ({http}) {
  return http.get('/items')
    // All status codes between 200 - 300, including 200
    .then((response) => {
      response.status // Status code of response
      response.result // Parsed response text
      // The response headers are returned as an object with lowercase header
      // names as keys. Values belonging to the same key are separated by ', '.
      response.headers // Parsed response headers
    })
    // All other status codes
    .catch((error) => {
      // HttpProviderError
      error.message // {status: 500, result: 'response text', headers: {}, isAborted: false}
    })
}

cors

Cors has been turned into a “black box” by jQuery. Cors is actually a very simple concept, but due to a lot of confusion of “Request not allowed”, cors has been an option to help out. In HttpProvider we try to give you the insight to understand how cors actually works.

Cors has nothing to do with the client. The only client configuration related to cors is the withCredentials option, which makes sure cookies are passed to the cross origin server. The only requirement for cors to work is that you pass the correct Content-Type. Now, this depends on the server in question. Some servers allows any content-type, others require a specific one. These are the typical ones:

  • text/plain
  • application/x-www-form-urlencoded
  • application/json; charset=UTF-8

Note that this is only related to the request. If you want to define what you want as response, you set the Accept header, which is application/json by default.