Etools Ajax Request Mixin & Module

Element for handling ajax requests. It uses the iron-request polymer component to make the requests. Exposes its functionality through a mixin and also through a module. The module functionality can be used in any framework, the mixin is Polymer dependent. For GET requests it can cache the data using Dexie db.

The <etools-ajax> is a Polymer element based on the EtoolsAjaxRequestMixin.

Data caching requirements

If you want to be able to cache the request data you must define your app Dexie db schema and then set it on window.EtoolsRequestCacheDb global variable. EtoolsAjaxRequestMixin behavior depends on it.

// custom dexie db that will be used by EtoolsAjaxRequestMixin
var appDexieDb = new Dexie('yourAppDexieDbName');
appDexieDb.version(1).stores({
  listsExpireMapTable: '&name, expire',
  ajaxDefaultDataTable: '&cacheKey, data, expire'
});

// configure app dexie db to be used for caching by EtoolsAjaxRequestMixin.
window.EtoolsRequestCacheDb = etoolsCustomDexieDb;

Only GET requests response data can be cached. For example, if your endpoint object looks like this:

var endpoint = {
  url: 'your/api/route',
  exp: 300000, // if exp = 0 no caching will be made
  cachingKey: 'dataSetIdentifierString'
};

then when the request response is received it will be cached into dexie db, default table: ajaxDefaultDataTable as an object like this:

{
  // cacheKey can have request params stringified in the end if params were provided in sendRequest options
  cacheKey: 'dataSetIdentifierString',
  // Date.now() + endpoint.exp
  expire: 1491306589975,
  // request response data
  data: response
}

Next time this request will be made, the data from cache will be returned if it did not expired. If cached data is expired or not found a new request will be sent.

To cache a list of objects (returned by request) in a specified table from Dexie db that you need later to make queries on it you have to use an endpoint like this:

var endpoint = {
  url: 'your/api/route',
  exp: 300000, // if exp = 0 no caching will be made
  cacheTableName: 'countries'
};

In this case countries table should be defined in Dexie db schema. The request response objects will be saved in this Dexie table. On next same request the data from this table will be returned if is not expired. In case data from this table(countries in our case) is expired a new request will be fired.

cacheTableName should be used only if you want to use Dexie functionality for making queries, like showing a list with pagination and filtering only on frontend side.

For more info about Dexie.js databases check the documentation.

Disable caching

Just set this in your app: window.EtoolsRequestCacheDisabled = true

Usage in version above 2.0.4 => Use it as a mixin instead of behavior

Usage in version 2.0.4 and below

// inside an element method (make sure ajax request mixin is included)
this.sendRequest({
  method: 'GET',
  endpoint: {
    url: '/countries-data'
  },
  params: {
    id: 10,
    country_name: 'USA'
  }
})
  .then(function (resp) {
    console.log(resp);
  })
  .catch(function (error) {
    console.log(error);
  });

sendRequest params:

An object that must have this properties

• method - any HTTP method, defaults to 'GET' if is not defined

• endpoint - an object that must contain the url property. For caching this object can have exp(time to cache data in milliseconds), cachingKey(any string) ,cacheTableName(the Dexie table name, where you can store a list of objects from server response) or sharedDbCachingKey. For more info on caching configuration see https://github.com/unicef-polymer/etools-dexie-caching Readme; token_key property holds the local storage key of the token. If present, the 'Authorization' header will be set. When token_key and window.AppMsalInstance are set, the token is automatically added to the request. If the token is expired, a silent token refresh will be done. If the silent token refresh errors out the page is reloaded in order to be redirected to the Sign in page.

  endpoint format:

  {
    url: string,
    exp?: number,
    cacheTableName?: string,
    cachingKey?: string,
    token_key?: string
  }

• params - request params, will be used to build url query string . It is recomended that etools-ajax receives the final form of the url it needs to call, so avoid using this.

• body - request body for POST | PUT | PATCH | DELETE methods

• csrfCheck - if other than disabled, x-csrftoken header will be set with value of csrftoken cookie

• headers - object of additional headers that can be set on request. Will automatically add 'language' header to the request if window.EtoolsLanguage is set.

• multiPart - if true it will take the body and convert it in FormData

• prepareMultipartData - used by etools apps to convert request complex json body to FromData and prefix objects properties with _obj

• timeout - Set the timeout flag on the request

• async - Toggle whether XHR is synchronous or asynchronous. Don't change this to true unless You Know What You Are Doing

• handleAs - Specifies what data to store in the response property, and to deliver as event.detail.response in response events. One of: text: uses XHR.responseText. xml: uses XHR.responseXML. json: uses XHR.responseText parsed as JSON. arraybuffer: uses XHR.response. blob: uses XHR.response. document: uses XHR.response.

• jsonPrefix - Prefix to be stripped from a JSON response before parsing it.

• rejectWithRequest - Changes the completes promise chain from generateRequest to reject with an object containing the original request, as well an error message. If false (default), the promise rejects with an error message only.

• withCredentials - Whether or not to send credentials on the request. Default is false.

Ajax response handling:

sendRequest will return a Promise:

• if request succeeded it will contain response data
• in case of error it will contain an object like this with this properties: error, statusCode, statusText, response

Abort requests

There are 2 properties used to track active and last requests:

• activeAjaxRequests - active ajax requests mapping, a list of objects like {key: 'someAjaxReqkey', request: activeRequest} used to manage all active requests.
• lastAjaxRequest - last request fired.

To abort any of the active requests you can use abortRequestByKey(key). You can also use this.lastAjaxRequest.abort() to abort last request.

Upload

upload method found in the upload-helper file can be used to upload files.

• optional param onProgressCallback can be a function to be called on upload progress

Install

TODO: create npm package

$ npm i --save @unicef-polymer/etools-ajax

Running Tests

TODO: improve tests & add more tests

You need to have web-component-tester installed (if not run npm install -g web-component-tester)

$ wct

or

$ wct -p

Circle CI

Package will be automatically published after tag push (git tag 1.2.3 , git push --tags). Tag name must correspond to SemVer (Semantic Versioning) rules.
Examples:

Version match	Result
1.2.3	match
1.2.3-pre	match
1.2.3+build	match
1.2.3-pre+build	match
v1.2.3-pre+build	match
1.2	no match

You can see more details here