Add a basic join server

README.md

@@ -3,6 +3,7 @@
 This repository contains a selection of command-line tools for administering Data Unions on Streamr:
 
 * [autokick](#binautokickjs)
+* [joinserver](#binjoinserverjs)
 
 ### Installation
 
@@ -78,3 +79,36 @@ Where the arguments are:
 * `--private-key [key]`: An Ethereum private key for an address that has been granted permissions to: 
   * Read data in all the streams given with `--stream`, and
   * Write to the join/part stream of your data union (not required in `--dry-run` mode, as you're not really kicking anybody)
+
+### bin/joinserver.js
+
+A http server to validate join requests to a Data Union. This can be used to implement custom validation for join requests, such as adding a CAPTCHA.
+
+The util ships with a dummy validation logic called `hardcoded` that simply checks that the requests contain a pre-defined secret. In real life, you'll want to implement your own validation logic and pass it to the script with the `--validation-logic` option. 
+
+To get help, just run `bin/joinserver.js` without any arguments:
+
+```
+Usage: joinserver.js --private-key [privateKeyHex] ...
+
+Options:
+  --help              Show help                                        [boolean]
+  --version           Show version number                              [boolean]
+  --private-key       Ethereum private key of the Data Union admin or join agent
+                                                                      [required]
+  --ethereum-rpc      Ethereum RPC URL to use                           [string]
+  --validation-logic  Loads the desired join request validation logic from
+                      src/joinserver folder. The default 'hardcoded' logic is a
+                      dummy logic that accepts requests that supply a hard-coded
+                      secret.                    [string] [default: "hardcoded"]
+  --port              TCP port to listen on for HTTP requests
+                                                       [number] [default: 16823]
+```
+
+The script must be run with a private key for a user that has the permission to join members to the Data Union.
+
+Once the join server is running, you can try it out by doing a HTTP request:
+
+```
+curl -v -H "Content-Type: application/json" -d "{\"secret\":\"my-very-secret-password\"}" http://localhost:16823/0x103efb97b56ac6c5e697e58812a1a0eaa2529b14/0x9e3d69305Da51f34eE29BfB52721e3A824d59e69
+```

bin/joinserver.js

@@ -0,0 +1,139 @@
+#!/usr/bin/env node
+const StreamrClient = require('streamr-client')
+const ethers = require('ethers')
+const express = require('express')
+const app = express()
+
+require('console-stamp')(console, { pattern: 'yyyy-mm-dd HH:MM:ss' })
+
+const options = require('yargs')
+    .usage('Usage: $0 --private-key [privateKeyHex] ...')
+    .option('private-key', {
+        default: undefined,
+        describe: 'Ethereum private key of the Data Union admin or join agent',
+    })
+    .option('ethereum-rpc', {
+        type: 'string',
+        describe: 'Ethereum RPC URL to use',
+        default: undefined,
+    })
+    .option('validation-logic', {
+        type: 'string',
+        describe: 'Loads the desired join request validation logic from src/joinserver folder. The default \'hardcoded\' logic is a dummy logic that accepts requests that supply a hard-coded secret.',
+        default: 'hardcoded',
+    })
+    .option('port', {
+        type: 'number',
+        describe: 'TCP port to listen on for HTTP requests',
+        default: 16823,
+    })
+    .demandOption(['private-key'])
+    .argv;
+
+const privateKeyWithPrefix = (options['private-key'].startsWith('0x') ? '' : '0x') + options['private-key']
+const wallet = new ethers.Wallet(privateKeyWithPrefix)
+console.log(`Configured with a private key for address: ${wallet.address}`)
+
+// Load the specified validation logic
+const ValidationLogic = require('../src/joinserver/' + options['validation-logic'])
+const logic = new ValidationLogic(options)
+console.log(`Validation logic: ${options['validation-logic']}`)
+
+/**
+ * StreamrClient setup
+ */
+const clientConfig = {
+    auth: {
+        privateKey: options['private-key']
+    }
+}
+
+if (options['ethereum-rpc']) {
+    clientConfig.ethereumRpc = options['ethereum-rpc'] // TODO: does not exist, need to make this configurable in client!
+}
+
+// Create client
+const streamr = new StreamrClient(clientConfig)
+streamr.on('error', (err) => {
+    console.error(err)
+})
+
+// Configure HTTP server
+app.use(express.json());
+app.post('/:mainchainContractAddress/:memberAddress', async (req, res) => {
+    // Has this address already joined?
+    try {
+        const stats = await streamr.getMemberStats(req.params.mainchainContractAddress, req.params.memberAddress)
+        if (stats.active) {
+            const msg = `Address ${req.params.memberAddress} is already a member of Data Union ${req.params.mainchainContractAddress}`
+            console.log(msg)
+            res.status(400).send({
+                code: 'ALREADY_JOINED',
+                message: msg
+            })
+            return
+        }
+    } catch (err) {
+        // Attempt to join if the status could not be verified in advance
+    }
+
+    // Call validation logic. Throws on failure.
+    try {
+        logic.validate(
+            req.params.mainchainContractAddress,
+            req.params.memberAddress,
+            req.body
+        )
+    } catch (err) {
+        const msg = `Address ${req.params.memberAddress} failed validation while attempting to join Data Union ${req.params.mainchainContractAddress}. Error: ${err.message}`
+        console.log(msg)
+        res.status(400).send({
+            code: 'VALIDATION_FAILED',
+            message: msg
+        })
+        return
+    }
+
+    // Join the member! (assumption: promise resolves when added successfully)
+    try {
+        await streamr.addMembers(req.params.mainchainContractAddress, [req.params.memberAddress])
+    } catch (err) {
+        console.error(err)
+        res.status(500).send({
+            code: 'JOIN_FAILED',
+            message: `Failed to add member ${req.params.memberAddress} to join Data Union ${req.params.mainchainContractAddress}. The error was: ${err.message}`
+        })
+        return
+    }
+
+    // Verify by querying stats after joining
+    try {
+        const stats = await streamr.getMemberStats(req.params.mainchainContractAddress, req.params.memberAddress)
+        if (!stats.active) {
+            const msg = `Failed to add member ${req.params.memberAddress} to join Data Union ${req.params.mainchainContractAddress}. The member never became active.`
+            console.error(msg)
+            res.status(500).send({
+                code: 'JOIN_FAILED',
+                message: msg,
+            })
+        } else {
+            res.status(200).send(stats)
+        }
+    } catch (err) {
+        console.error(err)
+        res.status(500).send({
+            code: 'STATE_UNREACHABLE',
+            message: `Could not verify that the member ${req.params.memberAddress} joined Data Union ${req.params.mainchainContractAddress} successfully, because the Data Union state could not be retrieved.`
+        })
+    }
+})
+
+console.log(`Port: ${options.port}`)
+app.listen(options.port, () => {
+    console.log('Data Union join server started.')
+})
+
+// Log unhandled rejection traces
+process.on('unhandledRejection', (err, p) => {
+    console.error('Unhandled Rejection at: Promise', p, 'err:', err, `stack:`, err.stack)
+})