Submitting a transaction via RESTful API (how to handle transactionid and timestamp)

Question

Problem: I am unable to POST a transaction via the RESTful API generated by the composer-rest-server. I am receiving statusCode 422; the transaction instance is not valid. However, the same example works in the Playground.

Scenario: I've set up a transaction called Offer in my .cto file which posts an offer to buy a house:

// Offer - Specifies an offer that a bidder places on a house listing with an associated price

transaction Offer {
  o Double bidPrice
  --> HouseListing listing
  --> Person bidder
}

The composer-rest-server has generated an API with the following JSON string to post a transaction of type Offer:

{
  "$class": "org.acme.purchasing.Offer",
  "bidPrice": 0,
  "listing": "string",
  "bidder": "string",
  "transactionId": "string",
  "timestamp": "2017-07-21T13:37:09.460Z"
}

I've since replaced this with a sample transaction using the following JSON code derived from the above example:

{
  "$class": "org.acme.purchasing.Offer",
  "bidPrice": 1000,
  "listing": "001",
  "bidder": "RJOHNSON",
  "transactionId": "1b9aa63c-dfad-4aad-a610-dfc80f2796b2",
  "timestamp": "2017-07-21T13:37:09.460Z"
}

The response returned is error code 422:

{
  "error": {
    "statusCode": 422,
    "name": "ValidationError",
    "message": "The `Offer` instance is not valid. Details: `transactionId` can't be set (value: \"1b9aa63c-dfad-4aad-a610-d...6b2\").",
    "details": {
      "context": "Offer",
      "codes": {
        "transactionId": [
          "absence"
        ]
      },
      "messages": {
        "transactionId": [
          "can't be set"
        ]
      }
    },
    "stack": "ValidationError: The `Offer` instance is not valid. Details: `transactionId` can't be set (value: \"1b9aa63c-dfad-4aad-a610-d...6b2\").\n    at /usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/dao.js:355:12\n    at ModelConstructor.<anonymous> (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/validations.js:566:11)\n    at ModelConstructor.next (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/hooks.js:93:12)\n    at ModelConstructor.<anonymous> (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/validations.js:563:23)\n    at ModelConstructor.trigger (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/hooks.js:83:12)\n    at ModelConstructor.Validatable.isValid (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/validations.js:529:8)\n    at /usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/dao.js:351:9\n    at doNotify (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/observer.js:155:49)\n    at doNotify (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/observer.js:155:49)\n    at doNotify (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/observer.js:155:49)\n    at doNotify (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/observer.js:155:49)\n    at Function.ObserverMixin._notifyBaseObservers (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/observer.js:178:5)\n    at Function.ObserverMixin.notifyObserversOf (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/observer.js:153:8)\n    at Function.ObserverMixin._notifyBaseObservers (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/observer.js:176:15)\n    at Function.ObserverMixin.notifyObserversOf (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/observer.js:153:8)\n    at Function.ObserverMixin._notifyBaseObservers (/usr/lib/node_modules/composer-rest-server/node_modules/loopback-datasource-juggler/lib/observer.js:176:15)"
  }
}

Now the strange thing is that I've deployed the same BNA onto the Hyperledger Composer Playground and am able to execute transactions of type Offer successfully.

Note that in the Playground, "transactionId" and "timestamp" are not specified as the Playground appears to take care of these values. For example, this is what Playground proposes to me initially:

{
  "$class": "org.acme.purchasing.Offer",
  "bidPrice": 0,
  "listing": "resource:org.acme.purchasing.HouseListing#id:7965",
  "bidder": "resource:org.acme.purchasing.Person#id:4441"
}

Can anyone advise why it's saying the Offer instance is not valid? My first thought was that it's not liking the string I'm placing in "transactionId" but another Stack Overflow post points out that the transactionId is just an arbitrary UUIDv4 string which I've generated already.

Update #1: Failing even with default demo

In order to ensure by BNA is error-free, I've deployed the default carauction-demo (resembles my example closely) onto my local Hyperledger Fabric instance and deployed the composer-rest-server. I've also deployed the same BNA into the Playground. All assets and participants were created identical in both from the Explorer (local instance) and Playground. When it comes time to submit an Offer transaction:

{
  "$class": "org.acme.vehicle.auction.Offer",
  "bidPrice": 800,
  "listing": "resource:org.acme.vehicle.auction.VehicleListing#L001",
  "member": "resource:org.acme.vehicle.auction.Member#member3@acme.org"
}

This JSON was generated by the Playground and succeeds there. Copy/paste/executing into the Explorer yields a status 500 error.

{
  "error": {
    "statusCode": 500,
    "name": "Error",
    "message": "error trying invoke chaincode. Error: chaincode error (status: 500, message: Error: Object with ID 'string' in collection with ID 'Asset:org.acme.vehicle.auction.VehicleListing' does not exist)",
    "stack": "Error: error trying invoke chaincode. Error: chaincode error (status: 500, message: Error: Object with ID 'string' in collection with ID 'Asset:org.acme.vehicle.auction.VehicleListing' does not exist)\n    at _initializeChannel.then.then.then.then.catch (/usr/lib/node_modules/composer-rest-server/node_modules/composer-connector-hlfv1/lib/hlfconnection.js:806:34)"
  }
}

I'm still at a lost as to what is wrong here.

Answer 1

So I have successfully executed Offer transactions (/POST). I think the '500' error is because there is a missing field ('string' type), or relationship in your Offer transaction via REST.

Using the example of the Car Auction network https://github.com/hyperledger/composer-sample-networks/blob/master/packages/carauction-network/models/auction.cto

Either of these Offer transactions using /POST were successful in Explorer:

{
  "$class": "org.acme.vehicle.auction.Offer",
  "bidPrice": 20,
  "listing": "org.acme.vehicle.auction.VehicleListing#100",
  "member": "org.acme.vehicle.auction.Member#a@b.com"
 }

OR

{
  "$class": "org.acme.vehicle.auction.Offer",
  "bidPrice": 20,
  "listing": "org.acme.vehicle.auction.VehicleListing#100",
  "member": "org.acme.vehicle.auction.Member#a@b.com",
  "timestamp": "2017-07-28T14:07:02.558Z"
}

responded with a 200 (SUCCESS) and a transactionId in Explorer:

{
  "$class": "org.acme.vehicle.auction.Offer",
  "bidPrice": 20,
  "listing": "org.acme.vehicle.auction.VehicleListing#100",
  "member": "org.acme.vehicle.auction.Member#a@b.com",
  "transactionId": "e75b9934-1f08-4daf-90db-702bbe4b8fa1"
}

This is my VehicleListing asset JSON for #100 above

{
  "$class": "org.acme.vehicle.auction.VehicleListing",
  "listingId": "100",
  "reservePrice": 50,
  "description": "string",
  "state": "FOR_SALE",
  "offers": [
    {
      "$class": "org.acme.vehicle.auction.Offer",
      "bidPrice": 50,
      "listing": "100",
      "member": "resource:org.acme.vehicle.auction.Member#a@b.com",
      "transactionId": "string123",
      "timestamp": "2017-07-28T14:07:02.825Z"
    }
  ],
  "vehicle": "resource:org.acme.vehicle.auction.Vehicle#123"
}

And I created asset for Vehicle 123 as well as Member a@b.com

Answer 2

After much experimentation and some searching, I've concluded that the problem was that NPM was installed using sudo (as root). I redid the installation as non-root and the problem has now been solved. Everything is working as expected.

Answer 3

Composer updates the transactionId itself as its generated, you cannot do this in your JSON and hence why you get the error. This is a Loopback -> Swagger conversion issue as it should not appear in a /POST REST operation - captured here https://github.com/hyperledger/composer/issues/663