refactor: serve handlers/middlewares

moved shared codes into serveUtils to reduce complexity

controllers/handlers/ServeStatic.js

@@ -20,7 +20,6 @@
 const contentDisposition = require('content-disposition')
 const etag = require('etag')
 const fs = require('fs')
-const parseRange = require('range-parser')
 const SimpleDataStore = require('./../utils/SimpleDataStore')
 const errors = require('./../errorsController')
 const paths = require('./../pathsController')
@@ -152,13 +151,6 @@ class ServeStatic {
     return stat
   }
 
-  /*
-   * Based on https://github.com/pillarjs/send/blob/0.18.0/index.js
-   * Copyright(c) 2012 TJ Holowaychuk
-   * Copyright(c) 2014-2022 Douglas Christopher Wilson
-   * MIT Licensed
-   */
-
   async #handler (req, res) {
     if (this.#options.ignorePatterns && this.#options.ignorePatterns.some(pattern => req.path.startsWith(pattern))) {
       return errors.handleNotFound(req, res)
@@ -176,90 +168,38 @@ class ServeStatic {
       return errors.handleNotFound(req, res)
     }
 
-    // ReadStream options
-    let len = stat.size
-    const opts = {}
-    let ranges = req.headers.range
-    let offset = 0
-
-    // set content-type
+    // Set Content-Type
     res.type(req.path)
 
-    // set header fields
+    // Set header fields
     await this.#setHeaders(req, res, stat)
 
-    // conditional GET support
-    if (serveUtils.isConditionalGET(req)) {
-      if (serveUtils.isPreconditionFailure(req, res)) {
-        return res.status(412).end()
-      }
-
-      if (serveUtils.isFresh(req, res)) {
-        return res.status(304).end()
-      }
+    // Conditional GET support
+    if (serveUtils.assertConditionalGET(req, res)) {
+      return res.end()
     }
 
-    // adjust len to start/end options
-    len = Math.max(0, len - offset)
-    if (opts.end !== undefined) {
-      const bytes = opts.end - offset + 1
-      if (len > bytes) len = bytes
-    }
-
-    // Range support
-    if (this.#options.acceptRanges && serveUtils.BYTES_RANGE_REGEXP.test(ranges)) {
-      // parse
-      ranges = parseRange(len, ranges, {
-        combine: true
-      })
-
-      // If-Range support
-      if (!serveUtils.isRangeFresh(req, res)) {
-        // range stale
-        ranges = -2
-      }
-
-      // unsatisfiable
-      if (ranges === -1) {
-        // Content-Range
-        res.header('Content-Range', serveUtils.contentRange('bytes', len))
-
-        // 416 Requested Range Not Satisfiable
-        return res.status(416).end()
-      }
-
-      // valid (syntactically invalid/multiple ranges are treated as a regular response)
-      if (ranges !== -2 && ranges.length === 1) {
-        // Content-Range
-        res.status(206)
-        res.header('Content-Range', serveUtils.contentRange('bytes', len, ranges[0]))
-
-        // adjust for requested range
-        offset += ranges[0].start
-        len = ranges[0].end - ranges[0].start + 1
-      }
-    } else if (req.method === 'GET' && this.setContentDisposition) {
-      // Only set Content-Disposition on complete GET requests
-      // Range requests are typically when streaming
-      await this.setContentDisposition(req, res)
-    }
-
-    // set read options
-    opts.start = offset
-    opts.end = Math.max(offset, offset + len - 1)
+    // ReadStream options with Content-Range support if required
+    const { options, length } = serveUtils.buildReadStreamOptions(req, res, stat, this.#options.acceptRanges)
 
     // HEAD support
     if (req.method === 'HEAD') {
       // If HEAD, also set Content-Length (must be string)
-      res.header('Content-Length', String(len))
+      res.header('Content-Length', String(length))
       return res.end()
     }
 
-    if (len === 0) {
+    // Only set Content-Disposition on initial GET request
+    // Skip for subsequent requests on non-zero start byte (e.g. streaming)
+    if (options.start === 0 && this.setContentDisposition) {
+      await this.setContentDisposition(req, res)
+    }
+
+    if (length === 0) {
       res.end()
     }
 
-    return this.#stream(req, res, fullPath, opts, len)
+    return this.#stream(req, res, fullPath, options, length)
   }
 
   async #setHeaders (req, res, stat) {
@@ -289,8 +229,8 @@ class ServeStatic {
     }
   }
 
-  async #stream (req, res, fullPath, opts, len) {
-    const readStream = fs.createReadStream(fullPath, opts)
+  async #stream (req, res, fullPath, options, length) {
+    const readStream = fs.createReadStream(fullPath, options)
 
     readStream.on('error', error => {
       readStream.destroy()
@@ -298,7 +238,7 @@ class ServeStatic {
     })
 
     // 2nd param will be set as Content-Length header (must be number)
-    return res.stream(readStream, len)
+    return res.stream(readStream, length)
   }
 
   get handler () {

controllers/middlewares/ServeLiveDirectory.js

@@ -62,29 +62,16 @@ class ServeLiveDirectory {
     this.#options = options
   }
 
-  /*
-   * Based on https://github.com/pillarjs/send/blob/0.18.0/index.js
-   * Copyright(c) 2012 TJ Holowaychuk
-   * Copyright(c) 2014-2022 Douglas Christopher Wilson
-   * MIT Licensed
-   */
-
   handler (req, res, file) {
-    // set content-type
+    // Set Content-Type
     res.type(file.extension)
 
-    // set header fields
+    // Set header fields
     this.#setHeaders(req, res, file)
 
-    // conditional GET support
-    if (serveUtils.isConditionalGET(req)) {
-      if (serveUtils.isPreconditionFailure(req, res)) {
-        return res.status(412).end()
-      }
-
-      if (serveUtils.isFresh(req, res)) {
-        return res.status(304).end()
-      }
+    // Conditional GET support
+    if (serveUtils.assertConditionalGET(req, res)) {
+      return res.end()
     }
 
     // HEAD support

controllers/middlewares/ServeStaticQuick.js

@@ -22,7 +22,6 @@
 const chokidar = require('chokidar')
 const etag = require('etag')
 const fs = require('fs')
-const parseRange = require('range-parser')
 const serveUtils = require('./../utils/serveUtils')
 const logger = require('./../../logger')
 
@@ -78,94 +77,33 @@ class ServeStaticQuick {
     this.#options = options
   }
 
-  /*
-   * Based on https://github.com/pillarjs/send/blob/0.18.0/index.js
-   * Copyright(c) 2012 TJ Holowaychuk
-   * Copyright(c) 2014-2022 Douglas Christopher Wilson
-   * MIT Licensed
-   */
-
   handler (req, res, stat) {
-    // ReadStream options
-    let len = stat.size
-    const opts = {}
-    let ranges = req.headers.range
-    let offset = 0
-
-    // set content-type
+    // Set Content-Type
     res.type(req.path)
 
-    // set header fields
+    // Set header fields
     this.#setHeaders(req, res, stat)
 
-    // conditional GET support
-    if (serveUtils.isConditionalGET(req)) {
-      if (serveUtils.isPreconditionFailure(req, res)) {
-        return res.status(412).end()
-      }
-
-      if (serveUtils.isFresh(req, res)) {
-        return res.status(304).end()
-      }
+    // Conditional GET support
+    if (serveUtils.assertConditionalGET(req, res)) {
+      return res.end()
     }
 
-    // adjust len to start/end options
-    len = Math.max(0, len - offset)
-    if (opts.end !== undefined) {
-      const bytes = opts.end - offset + 1
-      if (len > bytes) len = bytes
-    }
-
-    // Range support
-    if (this.#options.acceptRanges && serveUtils.BYTES_RANGE_REGEXP.test(ranges)) {
-      // parse
-      ranges = parseRange(len, ranges, {
-        combine: true
-      })
-
-      // If-Range support
-      if (!serveUtils.isRangeFresh(req, res)) {
-        // range stale
-        ranges = -2
-      }
-
-      // unsatisfiable
-      if (ranges === -1) {
-        // Content-Range
-        res.header('Content-Range', serveUtils.contentRange('bytes', len))
-
-        // 416 Requested Range Not Satisfiable
-        return res.status(416).end()
-      }
-
-      // valid (syntactically invalid/multiple ranges are treated as a regular response)
-      if (ranges !== -2 && ranges.length === 1) {
-        // Content-Range
-        res.status(206)
-        res.header('Content-Range', serveUtils.contentRange('bytes', len, ranges[0]))
-
-        // adjust for requested range
-        offset += ranges[0].start
-        len = ranges[0].end - ranges[0].start + 1
-      }
-    }
-
-    // set read options
-    opts.start = offset
-    opts.end = Math.max(offset, offset + len - 1)
+    // ReadStream options with Content-Range support if required
+    const { options, length } = serveUtils.buildReadStreamOptions(req, res, stat, this.#options.acceptRanges)
 
     // HEAD support
     if (req.method === 'HEAD') {
       // If HEAD, also set Content-Length (must be string)
-      res.header('Content-Length', String(len))
+      res.header('Content-Length', String(length))
       return res.end()
     }
 
-    if (len === 0) {
+    if (length === 0) {
       res.end()
     }
 
-    return this.#stream(req, res, stat, opts, len)
+    return this.#stream(req, res, stat, options, length)
   }
 
   // Returns a promise which resolves to true once ServeStaticQuick is ready
@@ -174,7 +112,9 @@ class ServeStaticQuick {
     if (this.#readyPromise === true) return Promise.resolve(true)
 
     // Create a promise if one does not exist for ready event
-    if (this.#readyPromise === undefined) { this.#readyPromise = new Promise((resolve) => (this.#readyResolve = resolve)) }
+    if (this.#readyPromise === undefined) {
+      this.#readyPromise = new Promise((resolve) => (this.#readyResolve = resolve))
+    }
 
     return this.#readyPromise
   }
@@ -255,9 +195,9 @@ class ServeStaticQuick {
     }
   }
 
-  #stream (req, res, stat, opts, len) {
+  #stream (req, res, stat, options, length) {
     const fullPath = this.directory + req.path
-    const readStream = fs.createReadStream(fullPath, opts)
+    const readStream = fs.createReadStream(fullPath, options)
 
     readStream.on('error', error => {
       readStream.destroy()
@@ -265,7 +205,7 @@ class ServeStaticQuick {
     })
 
     // 2nd param will be set as Content-Length header (must be number)
-    return res.stream(readStream, len)
+    return res.stream(readStream, length)
   }
 
   get middleware () {

controllers/utils/serveUtils.js

@@ -1,4 +1,5 @@
 const fresh = require('fresh')
+const parseRange = require('range-parser')
 
 const self = {
   BYTES_RANGE_REGEXP: /^ *bytes=/
@@ -116,4 +117,75 @@ self.parseTokenList = str => {
   return list
 }
 
+self.assertConditionalGET = (req, res) => {
+  if (self.isConditionalGET(req)) {
+    if (self.isPreconditionFailure(req, res)) {
+      res.status(412)
+      return true
+    }
+
+    if (self.isFresh(req, res)) {
+      res.status(304)
+      return true
+    }
+  }
+}
+
+self.buildReadStreamOptions = (req, res, stat, acceptRanges) => {
+  // ReadStream options
+  let length = stat.size
+  const options = {}
+  let ranges = req.headers.range
+  let offset = 0
+
+  // Adjust len to start/end options
+  length = Math.max(0, length - offset)
+  if (options.end !== undefined) {
+    const bytes = options.end - offset + 1
+    if (length > bytes) {
+      length = bytes
+    }
+  }
+
+  // Range support
+  if (acceptRanges && self.BYTES_RANGE_REGEXP.test(ranges)) {
+    // Parse
+    ranges = parseRange(length, ranges, {
+      combine: true
+    })
+
+    // If-Range support
+    if (!self.isRangeFresh(req, res)) {
+      // Stale
+      ranges = -2
+    }
+
+    // Unsatisfiable
+    if (ranges === -1) {
+      // Content-Range
+      res.header('Content-Range', self.contentRange('bytes', length))
+
+      // 416 Requested Range Not Satisfiable
+      return res.status(416).end()
+    }
+
+    // Valid (syntactically invalid/multiple ranges are treated as a regular response)
+    if (ranges !== -2 && ranges.length === 1) {
+      // Content-Range
+      res.status(206)
+      res.header('Content-Range', self.contentRange('bytes', length, ranges[0]))
+
+      // Adjust for requested range
+      offset += ranges[0].start
+      length = ranges[0].end - ranges[0].start + 1
+    }
+  }
+
+  // Set read options
+  options.start = offset
+  options.end = Math.max(offset, offset + length - 1)
+
+  return { options, length }
+}
+
 module.exports = self