[+] Anchoring schemas to CORD Network

[VenuChoudhary001]

C4GT 2023 | CORD Network #Issue

• This PR contains the 1st milestone of the project -

Anchoring schemas to the cord network

How It Works

• ENV VARIABLES. Add these in the application.yml file

  registry.cord.issuer_schema_url=http://localhost:5106/api/v1/schema
  registry.cord.issuer_registry_url=http://localhost:5106/api/v1/registry

• If you are using docker, then instead of localhost, either you can try adding dhiagent or docker gateway url

  • In order to find docker gateway url, in a terminal, enter the command
  
  

    $  docker network inspect bridge

• application.yml should be like this
  

• In order to create schemas in sunbird-rc, we are required to hit this endpoint : /api/v1/Schema .

• I have added an environment variable anchor_to_cord, which needs to be set to true if you want to anchor the schema to the chain

• Just when you hit the endpoint api/v1/Schema, once the definitionsManager of SunbirdRc confirms that no other schema with same name exists, then we go for anchoring it to the cord chain.

• In order to anchor it to the chain, we need to hit the api/v1/schema endpoint of Issuer Agent, which accepts the following schema :

  {
       "title":"",
       "description":" ",
       "property":{
           // schema 
       }
  }

• So, whenever you are creating a schema and want to anchor it to chain, you must pass a description property as well.

• Major changes have been made in these two files :

 java/registry/src/main/java/dev/sunbirdrc/registry/helper/RegistryHelper.java 

 java/registry/src/main/java/dev/sunbirdrc/registry/controller/RegistryEntityController.java 

• In the RegistryHelper.java
  a. I have defined this function

   public JsonNode anchorToCord(JsonNode rootNode) throws Exception{
     try{
  
     ObjectMapper objectMapper=new ObjectMapper();
         /* anchor schema */
     JsonNode schemaProperty=rootNode.get("schema");
     JsonNode convertedSchema=objectMapper.readTree(schemaProperty.asText());
     
     JsonNode schemaNode=convertedSchema.get("definitions");
     
     JsonNode properties=schemaNode.get(rootNode.get("name").asText());
     JsonNode getProperties=properties.get("properties");
     
     JsonNode createSchema=objectMapper.createObjectNode()
     .put("title",convertedSchema.get("title").asText())
     .put("description",convertedSchema.get("description").asText())
     .set("properties",properties.get("properties"));
     
     JsonNode schemaToBeAnchored=objectMapper.createObjectNode()
     .set("schema",createSchema);
     
     JsonNode anchoredSchema=anchorSchemaAPI(schemaToBeAnchored);
     logger.info("ANCHORED SCHEMA TO CORD CHAIN  {}",anchoredSchema);
     /* Anchoring registry to CORD */
     JsonNode registrySchema=objectMapper.createObjectNode()
     .put("title",convertedSchema.get("title").asText())
     .put("description",convertedSchema.get("description").asText())
     .put("schemaId",anchoredSchema.get("schemaId").asText());
     
     JsonNode registryId=anchorRegistryAPI(registrySchema);
     logger.info("REGISTRY ID GENERATED ON CORD {} ",registryId);
     
     ((ObjectNode)rootNode).set("cord_registry_id", registryId.get("registryId"));
     ((ObjectNode)rootNode).set("cord_schema_id", anchoredSchema.get("schemaId"));
     
         return rootNode;
     }catch(Exception e){
         logger.error("ERROR {}",e);
         return objectMapper.createObjectNode().put("ERROR","Exception occurred");
     }
  
  }
  

  b. This function creates a proper json structure to pass as a request body to the api/v1/schema endpoint of Issuer
  and calls the anchorSchemaAPI() and anchorRegistryAPI() defined in the same file.

    public JsonNode anchorSchemaAPI(JsonNode obj) throws Exception{
       JsonNode schema=apiHelper(obj,issuer_schema_url);
       return schema;
   }
   /** Anchors registry to the CORD NETWORK ,*/
   public JsonNode anchorRegistryAPI(JsonNode obj) throws Exception{
       JsonNode registryDetails=apiHelper(obj,issuer_registry_url);
       return registryDetails;
   }
  

• In the RegistryEntityController, under the mapping api/v1/{entityName}, I have added the following code

   if (anchorToCord) { 
       if("Schema".equals(entityName)){
         JsonNode getRootNode=registryHelper.anchorToCord(rootNode);
         newRootNode.set(entityName, getRootNode);
       }else{
         newRootNode.set(entityName,rootNode);
       }
     }else{
         newRootNode.set(entityName, rootNode);
     }

Screenshots

Schema creation & anchoring to chain

If you hit the api/v1/Schema/{id} endpoint, this is the response and you can see it works just fine.

[CyberCitizen01]

I think unnecessary spaces, comments and debug print statements should be removed.

[amarts]

LGTM.

I feel someone with more Java experience should review it once. Need a reference to documentation on this in commit log (or as a comment)