Can't interact with geth over http or ws from node.js express app

[j4ys0n]

Expected behavior

Can interact with node over http or ws from node.js express app

Actual behavior

over http:

(node:70270) UnhandledPromiseRejectionWarning: Error: Invalid JSON RPC response: ""
    at Object.InvalidResponse (/Users/jayson/Code/contract-cloud/ds/node_modules/web3/node_modules/web3-core-helpers/src/errors.js:42:16)
    at XMLHttpRequest.request.onreadystatechange (/Users/jayson/Code/contract-cloud/ds/node_modules/web3/node_modules/web3-providers-http/src/index.js:107:32)
    at XMLHttpRequestEventTarget.dispatchEvent (/Users/jayson/Code/contract-cloud/ds/node_modules/xhr2-cookies/xml-http-request-event-target.ts:44:13)
    at XMLHttpRequest._setReadyState (/Users/jayson/Code/contract-cloud/ds/node_modules/xhr2-cookies/xml-http-request.ts:219:8)

over ws:

(node:69632) UnhandledPromiseRejectionWarning: Error: connection not open on send()
    at Object.ConnectionError (/Users/jayson/Code/contract-cloud/ds/node_modules/web3/node_modules/web3-core-helpers/src/errors.js:69:23)
    at Object.ConnectionNotOpenError (/Users/jayson/Code/contract-cloud/ds/node_modules/web3/node_modules/web3-core-helpers/src/errors.js:48:21)
    at WebsocketProvider.send (/Users/jayson/Code/contract-cloud/ds/node_modules/web3/node_modules/web3-providers-ws/src/index.js:321:33)
    at RequestManager.send (/Users/jayson/Code/contract-cloud/ds/node_modules/web3/node_modules/web3-core-requestmanager/src/index.js:162:66)

Steps to reproduce the behavior

1. set up express api
2. use express endpoint/route to trigger web3 connection to geth
3. try to send anything to geth

Logs

I'm running a geth client with the --debug synced to ropsten and there are no related messages on the console.

Environment

node v12.16.3, web3 v1.2.9 (also tried 1.2.8), macOS 10.15 and Ubuntu 18

i've tried web3.eth.getAccounts() and something like:

    const c = new web3.eth.Contract(contract.abi);
    const from = {from: creator, gas: 3000000}
    const simple = c
      .deploy({data: contract.bytecode, arguments: [...values]})
      .send(from)

if i'm not running the express api in front of the web3 connection, everything works as desired. this only happens when the web3 connection is initiated from the express app.

[cgewecke]

@j4ys0n

The error messages indicate the connection isn't getting established. How are you instantiating Web3?

There is a simple Web3 Express example here that might be worth looking at. It uses Web3 0.2.x and would need to be updated for Web3 1.x. But it might help you identify some small issue in your code that's making it fail.

if i'm not running the express api in front of the web3 connection, everything works as desired. this only happens when the web3 connection is initiated from the express app.

This suggests it's not a Web3 issue per se, but a problem with the way you're using Express.

[j4ys0n]

Thanks for the example. Unfortunately, it doesn't really help. My app uses Typescript and ES6 classes. This could be a scoping issue on my part, but I'm not seeing it right now, and I've done similar things in the past. I would think that if I'm following the same patterns, and that was the issue, mongodb and web3 wouldn't work, but mongodb does work.

This is how I'm instantiating web3

    const reconnect = {
      auto: true,
      delay: 1000,
      maxAttempts: 10
    }
    this.web3 = new Web3()
    // const provider = new Web3.providers.WebsocketProvider(`ws://${NODE}`, {reconnect})
    const provider = new Web3.providers.HttpProvider(`http://${NODE}`)
    this.web3.setProvider(provider)

i've been trying ws and http, but only one at a time.

Even if I instantiate Web3 and try to interact with geth all in the same scope/function, i still get the result above.

[j4ys0n]

ok. dumb mistake. the ip address of my server with the geth node changed (without restarting the server, which is strange). 🤦🏼‍♂️
good to go.