feat: support for custom matching functions

Author: daviddias

README.md

@@ -122,7 +122,7 @@ ms.addHandler(<protocol>, <handlerFunc>, [<matchingFunc>])
 
 - `protocol` is a string identifying the protocol.
 - `handlerFunc` is a function of type `function (protocol, conn)` that will be called if there is a handshake performed on `protocol`.
-- `matchingFunc` is a function that receives a protocol and a callback and should call `callback(err, result)` where `err` is if there was a error on the matching function, and `result` is a boolean that represents if a match happened. The default `matchingFunc` is exact matching.
+- `matchingFunc` is a function that receives a protocol and a callback and should call `callback(err, result)` where `err` is if there was a error on the matching function, and `result` is a boolean that represents if a match happened. The default `matchingFunc` is exact matching. The exact signature should be: `function (protocol, requestedProtocol, function (err, result)`
 
 ### Selecting a protocol
 

package.json

@@ -40,6 +40,7 @@
   "author": "David Dias <daviddias@ipfs.io>",
   "license": "MIT",
   "dependencies": {
+    "async": "^2.1.2",
     "debug": "^2.2.0",
     "interface-connection": "^0.3.0",
     "lodash.isfunction": "^3.0.8",
@@ -64,4 +65,4 @@
     "Richard Littauer <richard.littauer@gmail.com>",
     "npm-to-cdn-bot (by Forbes Lindesay) <npmcdn-to-unpkg-bot@users.noreply.github.com>"
   ]
-}
+}

src/listener/index.js

@@ -4,8 +4,9 @@ const pull = require('pull-stream')
 const isFunction = require('lodash.isfunction')
 const assert = require('assert')
 const select = require('../select')
-const selectHandler = require('./selectHandler')
-const lsHandler = require('./lsHandler')
+const selectHandler = require('./select-handler')
+const lsHandler = require('./ls-handler')
+const matchExact = require('./match-exact')
 
 const util = require('./../util')
 const Connection = require('interface-connection').Connection
@@ -15,7 +16,11 @@ const PROTOCOL_ID = require('./../constants').PROTOCOL_ID
 module.exports = class Listener {
   constructor () {
     this.handlers = {
-      ls: (protocol, conn) => lsHandler(this, conn)
+      ls: {
+        handlerFunc: (protocol, conn) => lsHandler(this, conn),
+        matchFunc: matchExact
+
+      }
     }
     this.log = util.log.listener()
   }
@@ -50,14 +55,21 @@ module.exports = class Listener {
   }
 
   // be ready for a given `protocol`
-  addHandler (protocol, handler) {
+  addHandler (protocol, handlerFunc, matchFunc) {
     this.log('adding handler: ' + protocol)
-    assert(isFunction(handler), 'handler must be a function')
+    assert(isFunction(handlerFunc), 'handler must be a function')
 
     if (this.handlers[protocol]) {
       this.log('overwriting handler for ' + protocol)
     }
 
-    this.handlers[protocol] = handler
+    if (!matchFunc) {
+      matchFunc = matchExact
+    }
+
+    this.handlers[protocol] = {
+      handlerFunc: handlerFunc,
+      matchFunc: matchFunc
+    }
   }
 }

src/listener/lsHandler.js renamed to src/listener/ls-handler.js

@@ -0,0 +1,11 @@
+'use strict'
+
+function matchExact (myProtocol, senderProtocol, callback) {
+  if (myProtocol === senderProtocol) {
+    callback(null, true)
+  } else {
+    callback(null, false)
+  }
+}
+
+module.exports = matchExact

src/listener/match-exact.js

@@ -0,0 +1,76 @@
+'use strict'
+
+const handshake = require('pull-handshake')
+const lp = require('pull-length-prefixed')
+const Connection = require('interface-connection').Connection
+const writeEncoded = require('../util.js').writeEncoded
+const some = require('async/some')
+
+function selectHandler (rawConn, handlersMap, log) {
+  const cb = (err) => {
+    // incoming errors are irrelevant for the app
+    log.error(err)
+  }
+
+  const stream = handshake({ timeout: 60 * 1000 }, cb)
+  const shake = stream.handshake
+
+  next()
+  return stream
+
+  function next () {
+    lp.decodeFromReader(shake, (err, data) => {
+      if (err) {
+        return cb(err)
+      }
+      log('received:', data.toString())
+      const protocol = data.toString().slice(0, -1)
+
+      matcher(protocol, handlersMap, (err, result) => {
+        if (err) {
+          return cb(err)
+        }
+        const key = result
+
+        if (key) {
+          log('send ack back of: ' + protocol)
+          writeEncoded(shake, data, cb)
+
+          const conn = new Connection(shake.rest(), rawConn)
+          handlersMap[key].handlerFunc(protocol, conn)
+        } else {
+          log('not supported protocol: ' + protocol)
+          writeEncoded(shake, new Buffer('na\n'))
+          next()
+        }
+      })
+    })
+  }
+}
+
+module.exports = selectHandler
+
+function matcher (protocol, handlers, callback) {
+  const supportedProtocols = Object.keys(handlers)
+  let supportedProtocol = false
+
+  some(supportedProtocols,
+    (sp, cb) => {
+      handlers[sp].matchFunc(sp, protocol, (err, result) => {
+        if (err) {
+          return cb(err)
+        }
+        if (result) {
+          supportedProtocol = sp
+        }
+        cb()
+      })
+    },
+    (err) => {
+      if (err) {
+        return callback(err)
+      }
+      callback(null, supportedProtocol)
+    }
+  )
+}

src/listener/match-semver.js

@@ -97,7 +97,6 @@ describe('multistream handshake', () => {
         const protocol = '/monkey/1.0.0'
         msl.addHandler(protocol, (p, conn) => {
           expect(protocol).to.equal(p)
-          console.log(protocol)
           pull(conn, conn)
         })
         next()
@@ -340,3 +339,57 @@ describe('multistream handshake', () => {
     ], done)
   })
 })
+
+describe('custom matching function', () => {
+  it('match-true always', (done) => {
+    const p = pullPair()
+    const dialerConn = p[0]
+    const listenerConn = p[1]
+
+    let msl
+    let msd
+    series([
+      (next) => {
+        parallel([
+          (cb) => {
+            msl = new multistream.Listener()
+            expect(msl).to.exist
+            msl.handle(listenerConn, cb)
+          },
+          (cb) => {
+            msd = new multistream.Dialer()
+            expect(msd).to.exist
+            msd.handle(dialerConn, cb)
+          }
+        ], next)
+      },
+      (next) => {
+        msl.addHandler('/does-not-matter/1.0.0', (p, conn) => {
+          pull(conn, conn)
+        }, (myProtocol, requestedProtocol, callback) => {
+          callback(null, true)
+        })
+        next()
+      },
+      (next) => {
+        msd.select('/it-is-gonna-match-anyway/1.0.0', (err, conn) => {
+          expect(err).to.not.exist
+
+          pull(
+            pull.values(['banana']),
+            conn,
+            pull.collect((err, data) => {
+              expect(err).to.not.exist
+              expect(data).to.be.eql(['banana'])
+              next()
+            })
+          )
+        })
+      }
+    ], done)
+  })
+
+  describe('semver-match', () => {
+
+  })
+})