Add patch endpoint

Signed-off-by: James Taylor <jamest@uk.ibm.com>

README.md

@@ -68,20 +68,14 @@ Update an asset...
 curl --header "Content-Type: application/json" --request PUT --data '{"id":"asset7","color":"red","size":11,"owner":"Jean","appraisedValue":101}' http://localhost:3000/api/assets/asset7
 ```
 
+Transfer an asset...
+
+```shell
+curl --header "Content-Type: application/json" --request PATCH --data '[{"op":"replace","path":"/owner","value":"Ashleigh"}]' http://localhost:3000/api/assets/asset7
+```
+
 Delete an asset...
 
 ```shell
 curl -v -X DELETE http://localhost:3000/api/assets/asset7
 ```
-
-Or all of the above for complete chaos!
-
-```
-curl --request OPTIONS http://localhost:3000/api/assets/asset7 \
-  --next --header "Content-Type: application/json" --request POST --data '{"id":"asset7","color":"red","size":42,"owner":"Jean","appraisedValue":101}' http://localhost:3000/api/assets \
-  --next --request READ http://localhost:3000/api/assets/asset7 \
-  --next --header "Content-Type: application/json" --request PUT --data '{"id":"asset7","color":"red","size":11,"owner":"Jean","appraisedValue":101}' http://localhost:3000/api/assets/asset7 \
-  --next --request READ http://localhost:3000/api/assets/asset7 \
-  --next --request DELETE http://localhost:3000/api/assets/asset7 \
-  --next --request READ http://localhost:3000/api/assets/asset7
-```

asset-transfer-basic/rest-api-typescript/src/assets.router.ts

@@ -29,6 +29,7 @@ export const assetsRouter = express.Router();
 
 assetsRouter.post(
   '/',
+  body().isObject().withMessage('body must contain an asset object'),
   body('id', 'must be a string').notEmpty(),
   body('color', 'must be a string').notEmpty(),
   body('size', 'must be a number').isNumeric(),
@@ -122,7 +123,7 @@ assetsRouter.options('/:assetId', async (req: Request, res: Response) => {
       return res
         .status(OK)
         .set({
-          Allow: 'DELETE,GET,OPTIONS,PUT',
+          Allow: 'DELETE,GET,OPTIONS,PATCH,PUT',
         })
         .json({
           status: getReasonPhrase(OK),
@@ -174,6 +175,7 @@ assetsRouter.get('/:assetId', async (req: Request, res: Response) => {
 // TODO this shares a lot of code with the post endpoint!
 assetsRouter.put(
   '/:assetId',
+  body().isObject().withMessage('body must contain an asset object'),
   body('id', 'must be a string').notEmpty(),
   body('color', 'must be a string').notEmpty(),
   body('size', 'must be a number').isNumeric(),
@@ -261,6 +263,83 @@ assetsRouter.put(
   }
 );
 
+// TODO this shares a lot of code with the post endpoint!
+assetsRouter.patch(
+  '/:assetId',
+  body()
+    .isArray({
+      min: 1,
+      max: 1,
+    })
+    .withMessage('body must contain an array with a single patch operation'),
+  body('*.op', "operation must be 'replace'").equals('replace'),
+  body('*.path', "path must be '/owner'").equals('/owner'),
+  body('*.value', 'must be a string').isString(),
+  async (req: Request, res: Response) => {
+    logger.debug(req.body, 'Transfer asset request received');
+
+    const errors = validationResult(req);
+    if (!errors.isEmpty()) {
+      return res.status(BAD_REQUEST).json({
+        status: getReasonPhrase(BAD_REQUEST),
+        message: 'Invalid request body',
+        timestamp: new Date().toISOString(),
+        errors: errors.array(),
+      });
+    }
+
+    const assetId = req.params.assetId;
+    const newOwner = req.body[0].value;
+
+    const contract: Contract = req.app.get('contract');
+    const redis: Redis = req.app.get('redis');
+    const txn = contract.createTransaction('TransferAsset');
+    const txnId = txn.getTransactionId();
+    const txnState = txn.serialize();
+    const txnArgs = JSON.stringify([assetId, newOwner]);
+
+    try {
+      const timestamp = Date.now();
+
+      // Store the transaction details and set the event handler in case there
+      // are problems later with commiting the transaction
+      await storeTransactionDetails(redis, txnId, txnState, txnArgs, timestamp);
+      txn.setEventHandler(createDeferredEventHandler(redis));
+
+      await txn.submit(assetId, newOwner);
+
+      return res.status(ACCEPTED).json({
+        status: getReasonPhrase(ACCEPTED),
+        timestamp: new Date().toISOString(),
+      });
+    } catch (err) {
+      // TODO will this always catch endorsement errors or can those
+      // arrive later?
+
+      // There's no point retrying a transaction if there were business
+      // logic errors so clear the transaction details
+      //
+      // Note: it would be nice to pick out business logic errors returned
+      // from chaincode, e.g. asset already exists, and return those as a
+      // 400 error with message instead. Unfortunately the asset transfer
+      // sample or Fabric Node SDK do not provide any well defined error
+      // codes that can be checked.
+      await clearTransactionDetails(redis, txnId);
+
+      logger.error(
+        err,
+        'Error processing update asset request for asset ID %s with transaction ID %s',
+        req.params.assetId,
+        txnId
+      );
+      return res.status(INTERNAL_SERVER_ERROR).json({
+        status: getReasonPhrase(INTERNAL_SERVER_ERROR),
+        timestamp: new Date().toISOString(),
+      });
+    }
+  }
+);
+
 assetsRouter.delete('/:assetId', async (req: Request, res: Response) => {
   logger.debug(req.body, 'Delete asset request received');