This topic describes how to export data to an HTTP function of Function Compute by using data outflow rules in the Message Queue for MQTT console.

Procedure

The following figure shows the steps to export data to an HTTP function of Function Compute.

dg_flow_chart

Create an HTTP function of Function Compute

For more information about how to create an HTTP function of Function Compute, see Create an HTTP function and configure an HTTP trigger.

Note An HTTP function of Function Compute is used in the example of this topic. You can use this topic as a reference to export data to other types of HTTP services.

Create a Message Queue for MQTT instance

For more information about how to create a Message Queue for MQTT instance, see Create an instance.

Notice Only Message Queue for MQTT instances in the US (Virginia) and US (Silicon Valley) regions support data outflow to HTTP services. Make sure that your instances reside in the preceding regions.

Create a data source topic

For more information about how to create a data source topic, see Create a data source topic.

Create a data outflow rule

Create a data outflow rule to export data from data source topics of Message Queue for MQTT to the HTTP function of Function Compute.

  1. Log on to the Message Queue for MQTT console. In the top navigation bar, select the region where the instance is located.
  2. In the left-side navigation pane, click Rules.
  3. On the Rules page, click Create Rule.
  4. On the Create Rule panel, click the Data Outflow tab.
  5. On the Data Outflow tab, configure the following parameters as prompted and click OK.
    Type Parameter Required Example Description
    Rule Details Rule ID Yes fc_http_rule The ID of the rule. The value must meet the following requirements:
    • It can contain only letters, digits, hyphens (-), and underscores (_) and must contain at least one letter or digit.
    • It must be 3 to 64 characters in length. If the value contains more than 64 characters, it is automatically truncated.
    Rule Description Yes The data is exported to the HTTP function of Function Compute. The description of the rule.
    State Yes Enable Specifies whether to enable the rule. Valid values:
    • Enable
    • Disable
    Data Source Topic Yes fc-http-test The topic of the data source.
    Subscription Expression No None The expression of the subscription. If you do not specify Subscription Expression, all data under the data source topic is forwarded.
    • The expression supports the following delimiters:
      • Topic-level delimiter, which is a forward slash (/). Example: chat/teacher/room1.
      • Single-level wildcard, which is a plus sign (+). Example: chat/+.
      • Multi-level wildcard, which is a number sign (#). Example: chat/#.
    • You can add a maximum of five expressions.
    • The relationship between expressions is OR.
    • The expression, excluding the supported delimiters, can contain only letters, digits, hyphens (-), and underscores (_).
    • The expression can be a maximum of 64 characters in length.
    QOS No 1 The service quality of data transmission. If you do not set QOS, all data is forwarded by default. Valid values:
    • 0: indicates that data is distributed at most one time.
    • 1: indicates that data reaches the service at least one time.
    • 2: indicates that data is distributed only one time.
    Message Validity Period Yes 259200 The validity period of messages. If the TTL of a message is less than or equal to the value, the message is pushed. Unit: seconds. Valid Values: 1 to 259200.
    Flow Destination Type Yes HTTP The type of the destination to which you want export data.
    Endpoint Yes https://18807708****.cn-hangzhou.fc.aliyuncs.com/2016-08-15/proxy/fc_http_for_mqtt_test/fc_http_function_test/ The endpoint of the HTTP service. In this topic, the HTTP function of Function Compute is used. Therefore, you must enter the path that stores the HTTP trigger of the HTTP function of Function Compute.
    Notice The endpoint can be only a public endpoint.
    Retry Policy No None The retry policy after data outflow fails. If you do not set Retry Policy, no retries are performed by default.
    • The system supports a maximum of five retries.
    • The interval between retries is fixed to 60 seconds.
    On the Rules page, you can view the created rule in the Rule ID column.

(Optional) Perform security verification

After you create a rule that exports data to the HTTP function of Function Compute, Message Queue for MQTT generates a token for the rule. If you need to verify whether the HTTP requests that the HTTP function of Function Compute receives are from Message Queue for MQTT, you can use the token to perform signature verification.

  1. On the Rules page in the Message Queue for MQTT console, find the rule in the Rule ID column and click Details in the Actions column.
  2. In the Flow Destination section, click the icon_view icon and click the token to copy it.
  3. Modify the code of the HTTP function to verify the signature of the token based on the token and the following information.
    • The following code provides an example on HTTP requests:
      SignatureVersion=1.0
&Format=JSON
&SignatureNonce=ec4f2ea2-78bf-41a7-b1f7-1c9ba30c4d9b160625039****
&Message={
    "clientId":"GID_MQTT_CONSOLE@@@lmqshpre011606292****",
    "payload":"dGVzdA==",
    "qoslevel":"1",
    "topic":"fc-http-test"
}
&Version=2020-04-16
&RuleId=fc-http-test
&Signature=8H0vF0fZWTHMSxJUGDF****
&SignatureMethod=HMAC-SHA1
&Timestamp=2020-11-24T20:39:50Z
    • The following table describes the parameters in an HTTP request.
      Parameter Type Example Description
      SignatureVersion String 1.0 The version of the signature encryption algorithm. Set the value to 1.0.
      Format String JSON The format in which to return the response. Set the value to JSON.
      SignatureNonce String ec4f2ea2-78bf-41a7-b1f7-1c9ba30c4d9b160625039**** A unique, random number used to prevent replay attacks. You must use different random numbers for different requests.
      Message String The message content.
      clientId String GID_MQTT_CONSOLE@@@lmqshpre011606292**** The ID of the client.
      payload String dGVzdA== The message payload. To prevent HTTP request errors, Message Queue for MQTT Base64 encodes the message payload in the request. For example, if your original message payload is test, the Base64-encoded content is dGVzdA==.
      Notice If you need to retrieve the original message payload, you can call the Base64.decodeBase64() method to Base64 decode the content.
      qoslevel Integer 1 The service quality of data transmission.
      topic String fc-http-test The topic of the data source.
      Version String 2020-04-16 The version number of the API. The value is in the YYYY-MM-DD format. Set the value to 2020-04-20.
      RuleId String fc-http-test The ID of the rule.
      Signature String 8H0vF0fZWTHMSxJUGDF**** The signature string of the API request.
      SignatureMethod String HMAC-SHA1 The encryption method of the signature string. Set the value to HMAC-SHA1.
      Timestamp String 2020-11-24T20:39:50Z The timestamp of the request, which is in the date format. The time must be in the ISO 8601 standard in the yyyy-MM-ddTHH:mm:ssZ format. In addition, the time must be in UTC.
    • For more information about the signature algorithm for HTTP requests, see Signature method.

Use the SDK to connect your terminal to Message Queue for MQTT

Use the SDK for Message Queue for MQTT to connect your terminal to Message Queue for MQTT. This way, the data of your terminal can be exported to the HTTP function of Function Compute by using the data outflow rule. For more information about Message Queue for MQTT SDKs, see Download the SDK.