refactor: gateway resolver

Author: daviddias

src/http/gateway/resolver.js

@@ -12,35 +12,30 @@ const PathUtil = require('./utils/path')
 
 const INDEX_HTML_FILES = [ 'index.html', 'index.htm', 'index.shtml' ]
 
+function noop () {}
+
 const resolveDirectory = promisify((ipfs, path, multihash, callback) => {
-  if (!callback) {
-    callback = noop
-  }
+  callback = callback || noop
 
   mh.validate(mh.fromB58String(multihash))
 
-  ipfs
-   .object
-   .get(multihash, { enc: 'base58' })
-   .then((DAGNode) => {
-     const links = DAGNode.links
-     const indexFiles = links.filter((link) => INDEX_HTML_FILES.indexOf(link.name) !== -1)
+  ipfs.object.get(multihash, { enc: 'base58' }, (err, dagNode) => {
+    if (err) { return callback(err) }
 
-     // found index file in links
-     if (indexFiles.length > 0) {
-       return callback(null, indexFiles)
-     }
+    const links = dagNode.links
+    const indexFiles = links.filter((link) => INDEX_HTML_FILES.indexOf(link.name) !== -1)
 
-     return callback(null, html.build(path, links))
-   })
-})
+    // found index file in links
+    if (indexFiles.length > 0) {
+      return callback(null, indexFiles)
+    }
 
-const noop = function () {}
+    return callback(null, html.build(path, links))
+  })
+})
 
 const resolveMultihash = promisify((ipfs, path, callback) => {
-  if (!callback) {
-    callback = noop
-  }
+  callback = callback || noop
 
   const parts = PathUtil.splitPath(path)
   const partsLength = parts.length
@@ -53,62 +48,57 @@ const resolveMultihash = promisify((ipfs, path, callback) => {
     log('currentMultihash: ', currentMultihash)
     log('currentIndex: ', currentIndex, '/', partsLength)
 
-    ipfs
-     .object
-     .get(currentMultihash, { enc: 'base58' })
-     .then((DAGNode) => {
-      //  log('DAGNode: ', DAGNode)
-       if (currentIndex === partsLength - 1) {
-          // leaf node
-         log('leaf node: ', currentMultihash)
-        //  log('DAGNode: ', DAGNode.links)
-
-         if (DAGNode.links &&
-             DAGNode.links.length > 0 &&
-             DAGNode.links[0].name.length > 0) {
-           //  this is a directory.
-           let isDirErr = new Error('This dag node is a directory')
-           // add currentMultihash as a fileName so it can be used by resolveDirectory
-           isDirErr.fileName = currentMultihash
-           return next(isDirErr)
-         }
-
-         next()
-       } else {
-          // find multihash of requested named-file
-          // in current DAGNode's links
-         let multihashOfNextFile
-         const nextFileName = parts[currentIndex + 1]
-         const links = DAGNode.links
-
-         for (let link of links) {
-           if (link.name === nextFileName) {
-              // found multihash of requested named-file
-             multihashOfNextFile = mh.toB58String(link.multihash)
-             log('found multihash: ', multihashOfNextFile)
-             break
-           }
-         }
-
-         if (!multihashOfNextFile) {
-           log.error(`no link named "${nextFileName}" under ${currentMultihash}`)
-           throw new Error(`no link named "${nextFileName}" under ${currentMultihash}`)
-         }
-
-         currentMultihash = multihashOfNextFile
-         next()
-       }
-     })
+    ipfs.object.get(currentMultihash, { enc: 'base58' }, (err, dagNode) => {
+      if (err) { return next(err) }
+
+      if (currentIndex === partsLength - 1) {
+        // leaf node
+        log('leaf node: ', currentMultihash)
+
+        // TODO: Check if it is a directory by using Unixfs Type, right now
+        // it won't detect empty dirs
+        if (dagNode.links &&
+            dagNode.links.length > 0 &&
+            dagNode.links[0].name.length > 0) {
+          //  this is a directory.
+
+          let isDirErr = new Error('This dag node is a directory')
+          // add currentMultihash as a fileName so it can be used by resolveDirectory
+          isDirErr.fileName = currentMultihash
+          return next(isDirErr)
+        }
+        return next()
+      }
+
+      // find multihash of requested named-file in current dagNode's links
+      let multihashOfNextFile
+      const nextFileName = parts[currentIndex + 1]
+      const links = dagNode.links
+
+      for (let link of links) {
+        if (link.name === nextFileName) {
+          // found multihash of requested named-file
+          multihashOfNextFile = mh.toB58String(link.multihash)
+          log('found multihash: ', multihashOfNextFile)
+          break
+        }
+      }
+
+      if (!multihashOfNextFile) {
+        log.error(`no link named "${nextFileName}" under ${currentMultihash}`)
+        return next(new Error(`no link named "${nextFileName}" under ${currentMultihash}`))
+      }
+
+      currentMultihash = multihashOfNextFile
+      next()
+    })
   }, (err) => {
-    if (err) {
-      log.error(err)
-      return callback(err)
-    }
-    callback(null, {multihash: currentMultihash})
+    if (err) { return callback(err) }
+    callback(null, { multihash: currentMultihash })
   })
 })
 
 module.exports = {
-  resolveDirectory,
-  resolveMultihash
+  resolveDirectory: resolveDirectory,
+  resolveMultihash: resolveMultihash
 }