From 306f74635bc6ba71bf7788c55dceffad7cc6cb27 Mon Sep 17 00:00:00 2001
From: cel <cel@f/6sQ6d2CMxRUhLpspgGIulDxDCwYD7DzFzPNr7u5AU=.ed25519>
Date: Wed, 15 Jan 2020 10:35:04 -0500
Subject: Support blob range requests

---
 lib/serve.js | 86 +++++++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 68 insertions(+), 18 deletions(-)

(limited to 'lib')

diff --git a/lib/serve.js b/lib/serve.js
index b4efc58..afe494e 100644
--- a/lib/serve.js
+++ b/lib/serve.js
@@ -1506,24 +1506,74 @@ Serve.prototype.blob = function (id, path) {
       if (/^invalid/.test(err.message)) return self.respond(400, err.message)
       else return self.respond(500, err.message || err)
     }
-    pull(
-      self.app.getBlob(id, key),
-      pull.map(Buffer),
-      ident(gotType),
-      self.respondSink()
-    )
-    function gotType(type) {
-      type = type && mime.lookup(type)
-      if (type) self.res.setHeader('Content-Type', type)
-      // don't serve size for encrypted blob, because it refers to the size of
-      // the ciphertext
-      if (typeof size === 'number' && !key)
-        self.res.setHeader('Content-Length', size)
-      if (self.query.name) self.res.setHeader('Content-Disposition',
-        'inline; filename='+encodeDispositionFilename(self.query.name))
-      self.res.setHeader('Cache-Control', 'public, max-age=315360000')
-      self.res.setHeader('ETag', etag)
-      self.res.writeHead(200)
+    self.res.setHeader('Accept-Ranges', 'bytes')
+    var range = self.req.headers.range
+    if (range) {
+      if (self.req.headers['if-none-match'] === etag) return self.respond(304)
+      // TODO: support multiple ranges
+      var m = /^bytes=([0-9]*)-([0-9]*)$/.exec(range)
+      if (!m) return self.respond(416, 'Unable to parse range')
+      var start = m[1]
+      var last = m[2]
+      if (start === '') {
+        start = size - last
+        last = size - 1
+      } else if (last === '') {
+        start = Number(start)
+        last = size - 1
+      } else {
+        start = Number(start)
+        last = Number(last)
+      }
+      if (start > size || last >= size) return res.writeHead(416, 'Range not satisfiable')
+      var end = last + 1
+      var length = end - start
+      var wroteHeaders = false
+      pull(
+        // TODO: figure out how to use readBlobSlice for private blob range request
+        key ? pull(
+          self.app.getBlob(id, key),
+          u.pullSlice(start, end)
+        ) : self.app.readBlobSlice({
+          link: id,
+          size: size
+        }, {
+          start: start,
+          end: end,
+        }),
+        pull.through(function (buf) {
+          if (wroteHeaders) return
+          self.res.setHeader('Cache-Control', 'public, max-age=315360000')
+          self.res.setHeader('ETag', etag)
+          self.res.setHeader('Content-Length', length)
+          self.res.setHeader('Content-Range', 'bytes ' + start + '-' + last + '/' + size)
+          self.res.writeHead(206)
+          wroteHeaders = true
+        }),
+        pull.map(Buffer),
+        self.respondSink()
+      )
+
+    } else {
+      pull(
+        self.app.getBlob(id, key),
+        pull.map(Buffer),
+        ident(gotType),
+        self.respondSink()
+      )
+      function gotType(type) {
+        type = type && mime.lookup(type)
+        if (type) self.res.setHeader('Content-Type', type)
+        // don't serve size for encrypted blob, because it refers to the size of
+        // the ciphertext
+        if (typeof size === 'number' && !key)
+          self.res.setHeader('Content-Length', size)
+        if (self.query.name) self.res.setHeader('Content-Disposition',
+          'inline; filename='+encodeDispositionFilename(self.query.name))
+        self.res.setHeader('Cache-Control', 'public, max-age=315360000')
+        self.res.setHeader('etag', etag)
+        self.res.writeHead(200)
+      }
     }
   })
 }
-- 
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