Issue/4 - Handles the case where there are no /components/schemas but there is an anonymous one in an operation. (#13)

* First commit with samples.

* Work in progress.

* Work in progress.

* First commit with code worth sharing.

* Fixed merge messages in README.

* fixes #4 This template now works when the payload schema is embedded inside an operation, as is the case with the Streetlights demo.

Author: damaru-inc

README.md

@@ -9,7 +9,13 @@ Support for arrays, specifying function names and other features are yet to be i
 
 In the samples directory there is an example of code that is close to what we intend to generate.
 
-To run the sample code, copy config-template.ini to config.ini and enter your host and password.
+## Configuration
+
+To run the sample code, copy config-template.ini to config.ini and enter the connection details.
+
+If no authentication is needed, you need not provide the username and password values.
+
+If no host is given, the template attempts to find an mqtt host in the servers section of the AsyncAPI document to use instead.
 
 ## Specification Conformance
 Note that this template interprets the AsyncAPI document in conformance with the [AsyncAPI Specification](https://www.asyncapi.com/docs/specifications/2.0.0/).
@@ -29,6 +35,7 @@ Run the Generator using the Python Paho Template
 ag ~/AsyncApiDocument.yaml @asyncapi/python-paho-template
 ```
 
+Copy config-template.ini to config.ini and edit it to provide the connection details.
 
 ### Parameters
 
@@ -47,5 +54,3 @@ Extension | Parameter | Default | Description
 info.x-view | view | client | By default, this template generates publisher code for subscribe operations and vice versa. You can switch this by setting this parameter to 'provider'.
 
 
-
-

filters/all.js

@@ -20,6 +20,11 @@ function functionName([channelName, channel]) {
 }
 filter.functionName = functionName;
 
+function getAnonymousSchema(asyncapi) {
+  return anonymousSchema(asyncapi);
+}
+filter.getAnonymousSchema = getAnonymousSchema;
+
 function getRealSubscriber([info, params, channel]) {
   let pub = templateUtil.getRealSubscriber(info, params, channel);
   return pub
@@ -51,6 +56,45 @@ function identifierName(str) {
 }
 filter.identifierName = identifierName;
 
+// For files like the streetlights tutorial that don't have schemas, this finds the first anonymous schema in a message payload.
+function anonymousSchema(asyncapi) {
+  let ret = null;
+  for (channelName in asyncapi.channels()) {
+    let channel = asyncapi.channel(channelName);
+    let sub = channel.subscribe();
+    //console.log("anonymousSchema " + channelName);
+    //console.log("Sub:");
+    //console.log(sub);
+
+    if (sub) {
+      ret = anonymouseSchemaFromOperation(sub);
+    }
+
+    if (!ret) {
+      let pub = channel.publish();
+      //console.log("Pub:");
+      //console.log(pub)
+      if (pub) {
+        ret = anonymouseSchemaFromOperation(pub);
+      }
+    }
+
+    if (ret) {
+      return ret;
+    }
+  }
+}
+
+function anonymouseSchemaFromOperation(operation) {
+  let ret = null;
+  let payloadClass = filter.payloadClass(operation);
+  //console.log('anonymouseSchemaFromOperation ' + payloadClass);
+  if (payloadClass === 'Payload') {
+    ret = operation.message().payload();
+  }
+  return ret;
+}
+
 function logFull(obj) {
   console.log(obj);
   if (obj) {
@@ -62,13 +106,27 @@ function logFull(obj) {
 filter.logFull = logFull;
 
 
-// This returns the class name of the payload.
+// This returns the class name of the payload. If the schema is embedded, rather than a reference
+// to something in components/schemas, we return the name 'Payload' which will be the class we use for the payload.
 function payloadClass(operation) {
+  //console.log("payloadClass............");
   let ret = operation.message().payload().ext('x-parser-schema-id');
+  //console.log(ret);
+  if (ret.includes("anonymous-schema")) {
+    ret = "Payload";
+  }
   return ret;
 }
 filter.payloadClass = payloadClass;
 
+// This returns the first server it can find in the servers section, mainly to 
+// support the streetlights tutorial.
+function server(asyncapi) {
+  return templateUtil.getServer(asyncapi)
+}
+filter.server = server;
+
+
 // This returns an object containing information the template needs to render topic strings.
 function topicInfo([channelName, channel]) {
   let p = channel.parameters();
@@ -174,7 +232,7 @@ function dump(obj) {
 
 function getImports(schema) {
   let ret = '';
-  //console.log("getImports ----------------------------:");
+  //console.log("getImports");
   //console.log(getMethods(schema))
   //console.log(schema);
   var properties = schema.properties();
@@ -205,7 +263,7 @@ function getImports(schema) {
       }
     } else {
       let ref = property.ext('x-parser-schema-id');
-      if (ref) {
+      if (ref && !ref.includes('anonymous')) {
         let importName = _.lowerFirst(ref);
         ret += `from ${importName} import ${ref}\n`
       }
@@ -250,7 +308,10 @@ function getMessengers([params, asyncapi]) {
       messenger.functionName = getFunctionNameByChannel(channelName, channel);
       messenger.subscribeTopic = topicInfo.subscribeTopic;
       messenger.payload = sub.message().payload();
-      messenger.payloadClass = messenger.payload.ext('x-parser-schema-id');
+      //console.log("payload:");
+      //console.log(messenger.payload);
+      messenger.payloadClass = filter.payloadClass(sub);
+      //console.log(messenger.payloadClass);
       //console.log(messenger);
       ret.push(messenger);
     }
@@ -266,26 +327,27 @@ function getMessengers([params, asyncapi]) {
 filter.getMessengers = getMessengers;
 
 function getFirstPublisherMessenger([params, asyncapi]) {
+  //console.log('getFirstPublisherMessenger');
+  let ret = null;
   for (channelName in asyncapi.channels()) {
     let channel = asyncapi.channel(channelName);
     let pub = templateUtil.getRealPublisher(asyncapi.info(), params, channel);
-    //(pub);
+
     if (pub) {
       let messenger = {};
       messenger.name = _.camelCase(channelName) + "Messenger";
       messenger.functionName = getFunctionNameByChannel(channelName, channel);
       messenger.publishTopic = channelName;
       messenger.payload = pub.message().payload();
-      messenger.payloadClass = messenger.payload.ext('x-parser-schema-id');
-      //console.log(messenger.payloadClass);
-      //console.log(messenger.name);
-      return messenger;
+      messenger.payloadClass = filter.payloadClass(pub);
+      //console.log("getFirstPublisherMessenger messenger.payloadClass: " + messenger.payloadClass);
+      //console.log("getFirstPublisherMessenger messenger.name:         " + messenger.name);
+      ret =  messenger;
+      break;
     }
   }
-
-  let messenger = {};
-  messenger.name = "messenger";
-  return messenger;
+  //console.log('getFirstPublisherMessenger ' + ret);
+  return ret;
 }
 filter.getFirstPublisherMessenger = getFirstPublisherMessenger;
 

hooks/post-process.js

@@ -5,13 +5,24 @@ const _ = require('lodash');
 module.exports = {
   'generate:after': generator => {
     const asyncapi = generator.asyncapi;
+    let hasSchema = false;
 
-    for (schema in asyncapi.components().schemas()) {
-      let oldName = schema + ".py";
-      let newName = _.lowerFirst(oldName);
-      if (newName !== schema) {
-        fs.renameSync(path.resolve(generator.targetDir, oldName), path.resolve(generator.targetDir, newName));
+    if (asyncapi.components()) {
+
+      for (schema in asyncapi.components().schemas()) {
+        hasSchema = true;
+        let oldName = schema + ".py";
+        let newName = _.lowerFirst(oldName);
+        if (newName !== schema) {
+          fs.renameSync(path.resolve(generator.targetDir, oldName), path.resolve(generator.targetDir, newName));
+        }
       }
     }
+
+    // If there are no schemas, we expect to find an anonymous one embedded in a payload. If we do have schemas we assume we don't need this.
+    // This will turn out to be a bug if we ever have a file with schemas, but which also has an anonymous schema embedded in an operation.
+    if (hasSchema) {
+      fs.unlinkSync(path.resolve(generator.targetDir, 'payload.py'));
+    }
   }
 }

lib/templateUtil.js

@@ -67,6 +67,23 @@ class TemplateUtil {
 		return isProvider ? channel.subscribe() : channel.publish();
 	}
 
+	// This returns the first mqtt server we can find in the document.
+	getServer(asyncapi) {
+		let ret = 'None';
+		let servers = asyncapi.servers();
+		for (const name in servers) {
+			let server = asyncapi.server(name);
+			if (server.protocol() === 'mqtt') {
+				let url = server.url();
+				let i = url.lastIndexOf('/');
+				ret = url.substring(i + 1);
+				//console.log("getServer: " + url + " " + i + " " + ret);
+				break;
+			}
+		}
+		return ret;
+	}
+
 }
 
 // This is the set of Python reserved words, to ensure that we don't generate reserved words.

template/$$schema$$.py

@@ -4,4 +4,4 @@
 from entity import Entity
 {% set imports = schema | getImports %}
 {{ imports }}
-{{ modelClass(schemaName, schema.properties(), schema.required(), 0 ) }}
+{{ modelClass(schemaName, schema.properties(), schema.required(), 0 ) }}

template/config-template.ini

@@ -1,5 +1,5 @@
 [DEFAULT]
-host=our-host.messaging.solace.cloud
-password=your-password
-port=1883
-username=solace-cloud-client
+host=
+password=
+port=
+username=

template/main.py

@@ -5,10 +5,14 @@
 
 import messaging
 
+{% if asyncapi.components() -%}
 {% for schemaName, schema in asyncapi.components().schemas() -%}
 {% set moduleName = schemaName | lowerFirst -%}
 from {{ moduleName }} import {{ schemaName }}
-{% endfor %}
+{% endfor -%}
+{% else -%}
+from payload import Payload
+{% endif %}
 
 
 # Config has the connection properties.
@@ -36,23 +40,28 @@ def main():
     logging.basicConfig(level=logging.INFO)
     logging.info('Start of main.')
     config = getConfig()
+{% set publishMessenger = [params, asyncapi] | getFirstPublisherMessenger -%}
 {% set messengers = [params, asyncapi] | getMessengers -%}
 {%- for messenger in messengers -%}
 {%- if messenger.subscribeTopic %}
-    {{ messenger.name }} = messaging.Messaging(config, '{{ messenger.topic }}', {{ messenger.functionName }})
+    {{ messenger.name }} = messaging.Messaging(config, '{{ messenger.subscribeTopic }}', {{ messenger.functionName }})
 {%- else %}
     {{ messenger.name }} = messaging.Messaging(config)
 {%- endif %}
+{%- if publishMessenger %}
     {{ messenger.name }}.loop_start()
+{%- else %}
+    {{ messenger.name }}.loop_forever()
+{%- endif %}
 {%- endfor %}
-{% set messenger = [params, asyncapi] | getFirstPublisherMessenger -%}
-{%- if messenger %}
-    # Example of how to publish a message:
-    payload = {{ messenger.payloadClass }}()
+{%- if publishMessenger %}
+
+    # Example of how to publish a message. You will have to add arguments to the constructor on the next line:
+    payload = {{ publishMessenger.payloadClass }}()
     payloadJson = payload.to_json()
 
     while (True):
-        {{ messenger.name }}.publish('{{ messenger.publishTopic }}', payloadJson)
+        {{ publishMessenger.name }}.publish('{{ publishMessenger.publishTopic }}', payloadJson)
         time.sleep(1)
 {%- endif %}
 

template/messaging.py

@@ -10,6 +10,8 @@ class Messaging:
     def __init__(self, config, subscription = None, on_message = None, clientId = None):
         global on_connect
         self.config = config
+        defaultHost = '{{ asyncapi | server }}'
+        logging.info("Default host:", defaultHost)
 
         if (clientId):
             self.client = mqtt.Client(clientId)
@@ -25,9 +27,20 @@ def __init__(self, config, subscription = None, on_message = None, clientId = No
         if (on_message):
             self.client.on_message = on_message
 
-        self.client.username_pw_set(config['username'], config['password'])
-        port = int(config['port'])
-        self.client.connect(config['host'], port)
+        username = config.get('username', None)
+        password = config.get('password', None)
+
+        if username is not None:
+            self.client.username_pw_set(username, password)
+            
+        port = int(config.get('port', '1883'))
+        host = config.get('host', defaultHost)
+        print("Host: ", host, "port: ", port)
+
+        if host is None:
+            raise Exception("Host must be defined in the config file or in the servers section.")
+
+        self.client.connect(host, port)
 
     def publish(self, topic, payload, qos = 0, retain = False):
         self.client.publish(topic, payload, qos, retain)

template/payload.py

@@ -0,0 +1,10 @@
+{% from "partials/model-class" import modelClass -%}
+from enum import Enum
+from typing import Sequence
+from entity import Entity
+{% set schema = asyncapi | getAnonymousSchema -%}
+{% if schema %}
+{% set imports = schema | getImports -%}
+{{ imports }}
+{{ modelClass('Payload', schema.properties(), schema.required(), 0 ) }}
+{% endif %}