Add Date header and support If-None-Match

src/calibre/srv/errors.py

@@ -17,3 +17,11 @@ class MaxSizeExceeded(Exception):
 
     def __init__(self, prefix, size, limit):
         Exception.__init__(self, prefix + (' %d > maximum %d' % (size, limit)))
+
+class HTTP404(Exception):
+    pass
+
+class IfNoneMatch(Exception):
+    def __init__(self, etag=None):
+        Exception.__init__(self, '')
+        self.etag = etag

src/calibre/srv/http.py

@@ -13,9 +13,10 @@ from urllib import unquote
 from functools import partial
 
 from calibre import as_unicode
-from calibre.srv.errors import MaxSizeExceeded, NonHTTPConnRequest
+from calibre.srv.errors import (
+    MaxSizeExceeded, NonHTTPConnRequest, HTTP404, IfNoneMatch)
 from calibre.srv.respond import finalize_output, generate_static_output
-from calibre.srv.utils import MultiDict
+from calibre.srv.utils import MultiDict, http_date
 
 HTTP1  = 'HTTP/1.0'
 HTTP11 = 'HTTP/1.1'
@@ -436,7 +437,7 @@ class HTTPPair(object):
             self.flushed_write(msg.encode('ascii'))
         return True
 
-    def simple_response(self, status_code, msg=""):
+    def simple_response(self, status_code, msg="", read_remaining_input=False):
         abort = status_code in (httplib.REQUEST_ENTITY_TOO_LARGE, httplib.REQUEST_URI_TOO_LONG)
         if abort:
             self.close_connection = True
@@ -448,13 +449,32 @@ class HTTPPair(object):
         buf = [
             '%s %d %s' % (self.reponse_protocol, status_code, httplib.responses[status_code]),
             "Content-Length: %s" % len(msg),
-            "Content-Type: text/plain; charset=UTF-8"
+            "Content-Type: text/plain; charset=UTF-8",
+            "Date: " + http_date(),
         ]
         if abort and self.reponse_protocol is HTTP11:
             buf.append("Connection: close")
         buf.append('')
         buf = [(x + '\r\n').encode('ascii') for x in buf]
         buf.append(msg)
+        if read_remaining_input:
+            self.input_reader.read()
+        self.flushed_write(b''.join(buf))
+
+    def send_not_modified(self, etag=None):
+        buf = [
+            '%s %d %s' % (self.reponse_protocol, httplib.NOT_MODIFIED, httplib.responses[httplib.NOT_MODIFIED]),
+            "Content-Length: 0",
+            "Date: " + http_date(),
+        ]
+        if etag is not None:
+            buf.append('ETag: ' + etag)
+        for header in ('Expires', 'Cache-Control', 'Vary'):
+            val = self.outheaders.get(header)
+            if val:
+                buf.append(header + ': ' + val)
+        buf.append('')
+        buf = [(x + '\r\n').encode('ascii') for x in buf]
         self.flushed_write(b''.join(buf))
 
     def flushed_write(self, data):
@@ -475,13 +495,24 @@ class HTTPPair(object):
         else:
             self.input_reader = FixedSizeReader(self.conn.socket_file, self.request_content_length)
 
-        output = self.handle_request(self)
+        try:
-        if self.status_code is None:
+            output = self.handle_request(self)
-            raise Exception('Request handler did not set status_code')
+        except HTTP404 as e:
+            self.simple_response(httplib.NOT_FOUND, e.message, read_remaining_input=True)
+            return
         # Read and discard any remaining body from the HTTP request
         self.input_reader.read()
+        if self.status_code is None:
+            raise Exception('Request handler did not set status_code')
 
-        self.status_code, output = finalize_output(output, self.inheaders, self.outheaders, self.status_code)
+        try:
+            self.status_code, output = finalize_output(output, self.inheaders, self.outheaders, self.status_code, self.response_protocol is HTTP1, self.method)
+        except IfNoneMatch as e:
+            if self.method in ('GET', 'HEAD'):
+                self.send_not_modified(e.etag)
+            else:
+                self.simple_response(httplib.PRECONDITION_FAILED)
+            return
 
         self.send_headers()
 

src/calibre/srv/respond.py

@@ -10,6 +10,7 @@ import os, hashlib, shutil, httplib, zlib, struct, time
 from io import DEFAULT_BUFFER_SIZE, BytesIO
 
 from calibre import force_unicode
+from calibre.srv.errors import IfNoneMatch
 
 def acceptable_encoding(val, allowed=frozenset({'gzip'})):
     def enc(x):
@@ -75,7 +76,7 @@ class FileSystemOutputFile(object):
         pos = output.tell()
         output.seek(0, os.SEEK_END)
         self.content_length = output.tell() - pos
-        self.etag = hashlib.sha1(force_unicode(output.name or '') + str(os.fstat(output.fileno()).st_mtime)).hexdigest()
+        self.etag = hashlib.sha1(type('')(os.fstat(output.fileno()).st_mtime) + force_unicode(output.name or '')).hexdigest()
         output.seek(pos)
         self.accept_ranges = True
 
@@ -141,7 +142,10 @@ def generate_static_output(cache, gso_lock, name, generator):
             ans = cache[name] = StaticGeneratedOutput(generator())
         return ans
 
-def finalize_output(output, inheaders, outheaders, status_code):
+def parse_if_none_match(val):
+    return {x.strip() for x in val.split(',')}
+
+def finalize_output(output, inheaders, outheaders, status_code, is_http1, method):
     ct = outheaders.get('Content-Type', '')
     compressible = not ct or ct.startswith('text/') or ct.startswith('image/svg') or ct.startswith('application/json')
     if isinstance(output, file):
@@ -153,20 +157,29 @@ def finalize_output(output, inheaders, outheaders, status_code):
     else:
         output = GeneratedOutput(output, outheaders)
     compressible = (status_code == httplib.OK and compressible and output.content_length > 1024 and
-                    acceptable_encoding(inheaders.get('Accept-Encoding', '')))
+                    acceptable_encoding(inheaders.get('Accept-Encoding', '')) and not is_http1)
-    accept_ranges = not compressible and output.accept_ranges is not None and status_code == httplib.OK
+    accept_ranges = (not compressible and output.accept_ranges is not None and status_code == httplib.OK and
+                     not is_http1)
+    ranges = None
 
-    for header in 'Accept-Ranges Content-Encoding Transfer-Encoding ETag'.split():
+    for header in ('Accept-Ranges', 'Content-Encoding', 'Transfer-Encoding', 'ETag', 'Content-Length'):
         outheaders.pop('header', all=True)
 
-    # TODO: If-None-Match, Ranges, If-Range
+    none_match = parse_if_none_match(inheaders.get('If-None-Match', ''))
+    matched = '*' in none_match or (output.etag and output.etag in none_match)
+    if matched:
+        raise IfNoneMatch(output.etag)
 
-    if output.etag:
+    # TODO: Ranges, If-Range
+
+    if output.etag and method in ('GET', 'HEAD'):
         outheaders.set('ETag', output.etag, replace=True)
     if accept_ranges:
         outheaders.set('Accept-Ranges', 'bytes', replace=True)
     elif compressible:
         outheaders.set('Content-Encoding', 'gzip', replace=True)
+    if output.content_length is not None and not compressible and not ranges:
+        outheaders.set('Content-Length', '%d' % output.content_length, replace=True)
 
     if compressible or output.content_length is None:
         outheaders.set('Transfer-Encoding', 'chunked', replace=True)

src/calibre/srv/utils.py

@@ -8,8 +8,12 @@ __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from urlparse import parse_qs
 import repr as reprlib
+from email.utils import formatdate
 
-class MultiDict(dict):
+def http_date(timeval=None):
+    return type('')(formatdate(timeval=timeval, usegmt=True))
+
+class MultiDict(dict):  # {{{
 
     def __setitem__(self, key, val):
         vals = dict.get(self, key, [])
@@ -75,3 +79,4 @@ class MultiDict(dict):
 
     def pretty(self, leading_whitespace=''):
         return leading_whitespace + ('\n' + leading_whitespace).join('%s: %s' % (k, v) for k, v in self.items())
+# }}}