WeChat small program cloud development initialization

Initialization

Before you start using cloud capabilities on the smaller side, you need to call the wx.cloud.init method to initialize cloud capabilities (note that the small program needs to start the cloud service by clicking the "console" button in the upper left corner of the toolbar). Therefore, if we want to use cloud capabilities, we usually call this method when the small program is initialized.

The wx.cloud.init method is defined as follows:

function init(options): void

The wx.cloud.init method accepts an optional options argument, and the method does not return a value.

The options parameter defines the default configuration for cloud development, which serves as the default configuration for all other cloud APIs that are called later, and options provide the following optional configuration:

When env is passed in as an object, you can specify the default environment for each service, with the following optional fields:

Sample code:

wx.cloud.init({
  env: 'test-x1dzi'
})

Cloud functions initialization

The CLOUD.INIT method is defined as follows:

function init(options): void

Cloud.init method accepts an optional options parameter that does not return a value.The method can only call once, and only the first call takes effect multiple times.

The Options parameter defines the default configuration of the cloud development. This configuration will then call the default configuration of all other cloud APIs, and options provided by Options are as follows:

When the ENV passes the parameter, you can specify the default environment of each service, the optional fields are as follows:

Note: The env setting will only determine the cloud environment for this cloud function API call, not the environment in which the API is called in the other tuned cloud functions, and the environment needs to be reset by the init method in other tuned cloud functions.

Recommendation: Specify cloud when setting up env. DYNAMIC_CURRENT_ENV constant (SDK v1.1.0 or above) so that when a database request, storage request, or other cloud function is initiated within a cloud function, the default requested cloud environment is the environment in which the cloud function is currently located:

const cloud = require('wx-server-sdk')
cloud.init({
  env: cloud.DYNAMIC_CURRENT_ENV
})

exports.main = async (event) => {
  const { ENV, OPENID, APPID } = cloud.getWXContext()

  // 如果云函数所在环境为 abc，则下面的调用就会请求到 abc 环境的数据库
  const dbResult = await cloud.database().collection('test').get()

  return {
    dbResult,
    ENV,
    OPENID,
    APPID,
  }
}

Note: The value of the env parameter in the above code cannot be used with cloud.getWXContext(). ENV overrides because getWXContext() called outside exports.main cannot get to the current environment

API style

The API style for cloud development is consistent with the framework components and API style, but also supports callback and Promise styles. I n the Object parameter of the incoming API, if the success, fail, and complete fields are passed in, we think it's a callback style, and the API method call doesn't return Promise. If the three fields of success, fail, and complete do not exist in the Object parameters of the incoming API, then we think it is in Promise style, and the API method call returns a parameter, and the result of Promise Resolve is the same as the argument of the incoming success callback, and the result of reject is the same as the argument of the incoming fail.

Precautions

• If the env parameter is not passed on at init, subsequent API calls will default to the environment created, but this approach is not always expected, so this approach is obsolete, so be sure to explicitly pass in the env parameter