11.4. Sending documents with blockchain support

We will now create document with full blockchain support and send it to our contact. In this example we will use our stored blockchain keys we got in creating new companies section.

Please open BlockChain Add Files and send folder in Postman Integration Examples. Creating Envelope, adding files and sealing envelope are same as in creating new companies section. The only difference is document_type - now is MBL, which has full blockchain support. Everything is set in examples, so you just click through it.

Tip

We don't describe specific calls and responses here - it's easy to see them right in Postman. On every request call you can see what call is being made, what headers, body and parameters we send and what response we fetch. Also check Tests tab - there we check the response and parse some data from it.

11.4.1. Generating issue hash

After sealing envelope we click on Generate issue hash. Since we want to send blockchain supported document, we get an 407 - Unknown status with body:

{
   "status": "Not enough credits."
}

If you are working in sandbox environment please contact CargoX support, to top up you test company with some credits.

After CargoX support adds credits to our test company, we can again send Generate issue hash request. this time we get 200 OK response with JSON body. In the next step we will sign hash from relayed_transaction with our blockchain key.

11.4.2. Sign hash with blockchain key and send envelope

In this example we will use external service and metamask for signing message with blockchain key. When implementing integration programmatically check the API and examples sections for more help.

First, install metamask, follow instructions here: https://metamask.io/. Then, import test company blockchain key: https://metamask.zendesk.com/hc/en-us/articles/360015489331-How-to-import-an-Account

As said, we will use external service for signing message: https://www.myetherwallet.com/. Connect to https://www.myetherwallet.com/wallet/access with newly imported wallet (select "Browser Extension") and head to https://www.myetherwallet.com/wallet/sign/ section. Copy-paste hash from previous request and sign it with metamask. The end result should be like this:

We will need sig data - that is actual signed hash. In the next request - sending documents via blockchain to our contact, we copy-paste entire response from Generate issue hash request and add signed hash from mycrypto.com as signature field to it. This we add into JSON:

{"action":"issue","data": "RESPONSE FROM GENERATE ISSUE HASH + SIGNED HASH}

Entire Request body for this example (data will be different when you send it):

{"action":"issue","data":
      [
          {
              "document_token_id": "2ec589b8-9637-45f3-b940-09f376fe4bd0",
              "relayed_transaction": {
                  "hash": "0xe314477182e70b34581dbd0fc8073ff98eb58260c35e1532dd4a41230fe43079",
                  "relay_nonce": 1,
                  "recipient": "0xc8e04f362dB54e3FFeE14fC173f231B1A09DE851",
                  "relayed_for": "0xaA1116C4ce9f195D9730EF4CF803cA5d2bcAD868",
                  "signature": "b8412d807ac8532d4e6733e8be3a9795e33ba3065b2425725380be1c74347d91538a8b61c907af8ce20af31951e4e811222162f962670d890387edcb9e80a4ac1c",
                  "transaction_data": "0x3266df5b00000000000000000000000065902b6f61181650a9c5488d580c420acf6a9463000000000000000000000000000000002ec589b8963745f3b94009f376fe4bd06a08172c4205ea4fa51fb7b4fea6ed4d3789eb986d3bf1213094c8e110cfec9300000000000000000000000000000000000000000000000000000000000000120000000000000000000000000000000000000000000000000000000000000020000000000000000000000000ef8fa3588f2574c1665dabd27a8b029e1e52c4e00000000000000000000000000000000000000000000000000000000000000001"
              }
          }
      ]
   }

When we send the request we can see that we get a 200 OK response:

We can also see that envelope with blockchain document was delivered to test company2