From 7ea2eae3318ac3b7e602200c958507c447b7d14c Mon Sep 17 00:00:00 2001
From: Marcin Rataj <lidel@lidel.org>
Date: Wed, 24 Jul 2019 13:26:08 +0200
Subject: [PATCH] refactor: remove the need for swarm connect

This removes all code that caused swarm connect calls from delegate to
self. It was not needed: delegate is one of bootstrap nodes,
so we are always connected to it.

https://github.com/libp2p/js-libp2p-delegated-content-routing/issues/12#issuecomment-514591525

License: MIT
Signed-off-by: Marcin Rataj <lidel@lidel.org>
---
 src/index.js | 51 ++-------------------------------------------------
 1 file changed, 2 insertions(+), 49 deletions(-)

diff --git a/src/index.js b/src/index.js
index c660197..973716d 100644
--- a/src/index.js
+++ b/src/index.js
@@ -4,7 +4,6 @@ const dht = require('ipfs-http-client/src/dht')
 const swarm = require('ipfs-http-client/src/swarm')
 const refs = require('ipfs-http-client/src/files-regular/refs')
 const defaultConfig = require('ipfs-http-client/src/utils/default-config')
-const multiaddr = require('multiaddr')
 const { default: PQueue } = require('p-queue')
 const pMemoize = require('p-memoize')
 const debug = require('debug')
@@ -19,18 +18,6 @@ const DEFAULT_IPFS_API = {
   host: 'node0.delegate.ipfs.io'
 }
 
-// assuming below nodes need have autorelay enabled
-const DEFAULT_BOOSTRAP_NODES = [
-  '/ipfs/QmSoLer265NRgSp2LA3dPaeykiS1J6DifTC88f5uVQKNAd',
-  '/ipfs/QmSoLMeWqB7YGVLJN3pNLQpmmEk35v6wYtsMGLzSr5QBU3',
-  '/ipfs/QmSoLPppuBtQSGwKDZT2M73ULpjvfd3aZ6ha4oFGL1KrGM',
-  '/ipfs/QmSoLSafTMBsPKadTEgaXctDQVcqN88CNLHXMkTNwMKPnu',
-  '/ipfs/QmSoLueR4xBeUbY9WZ9xGUUxunbKWcrNFTDAadQJmocnWm',
-  '/ipfs/QmSoLV4Bbm51jM9C4gDYZQ9Cy3U6aXMJDAbzgu2fzaDs64',
-  '/ipfs/QmZMxNdpMkewiVZLMRxaNxUeZpDUb34pWjZ1kZvsd16Zic',
-  '/ipfs/Qmbut9Ywz9YEDrz8ySBSgWyJk41Uvm2QJPhwDJzJyGFsD6'
-]
-
 const CONCURRENT_HTTP_REQUESTS = 4
 const SWARM_CONNECT_MAX_AGE = 60e3
 
@@ -43,9 +30,8 @@ class DelegatedContentRouting {
    *
    * @param {PeerID} peerId - the id of the node that is using this routing.
    * @param {object} [api] - (Optional) the api endpoint of the delegated node to use.
-   * @param {Array<Multiaddr>} [bootstrappers] - (Optional) list of bootstrapper nodes we are connected to.
    */
-  constructor (peerId, api, bootstrappers) {
+  constructor (peerId, api) {
     if (peerId == null) {
       throw new Error('missing self peerId')
     }
@@ -58,11 +44,6 @@ class DelegatedContentRouting {
     this.refs = refs(this.api)
     this.peerId = peerId
 
-    bootstrappers = bootstrappers || DEFAULT_BOOSTRAP_NODES.map((addr) => multiaddr(addr))
-    this.circuits = bootstrappers.map((addr) => {
-      return addr.encapsulate(`/p2p-circuit/ipfs/${this.peerId.toB58String()}`)
-    })
-
     // limit concurrency to avoid request flood in web browser
     // https://github.com/libp2p/js-libp2p-delegated-content-routing/issues/12
     const concurrency = { concurrency: CONCURRENT_HTTP_REQUESTS }
@@ -104,7 +85,7 @@ class DelegatedContentRouting {
    * Announce to the network that the delegated node can provide the given key.
    *
    * Currently this uses the following hack
-   * - call swarm.connect on the delegated node to us, to ensure we are connected
+   * - delegate is one of bootstrap nodes, so we are always connected to it
    * - call refs on the delegated node, so it fetches the content
    *
    * @param {CID} key
@@ -114,34 +95,6 @@ class DelegatedContentRouting {
   async provide (key) {
     const keyString = key.toBaseEncodedString()
     log('provide starts: ' + keyString)
-
-    let results
-    try {
-      // optimization: try the first addr
-      // (swarm.connect will return success if ANY connection to this.peerId already exists)
-      const addr = this.circuits.find(a => Boolean(a))
-      const res = await this._httpQueue.add(() => this.swarm.connect(addr.toString()))
-      if (res && res.error) throw new Error() // trigger fallback
-      results = [res]
-    } catch (err) {
-      // fallback to trying all potential circuits
-      results = await Promise.all(
-        this.circuits.map((addr) =>
-          this._httpQueue.add(() =>
-            this.swarm.connect(addr.toString()).catch(() => {})
-          )
-        )
-      )
-    }
-    // only some need to succeed
-    const success = results.filter((res) => res && res.error == null)
-
-    if (success.length === 0) {
-      throw new Error('unable to swarm.connect using p2p-circuit')
-    }
-
-    // async preload of data to delegate node
-    // note: we call `provide` for every block, so it does not need to be recursive
     await this._httpQueueRefs.add(() =>
       this.refs(keyString, { recursive: false })
     )