Ticket #443: short-circuit-imm-etag.diff.txt

Thu Mar 11 16:18:11 PST 2010  Jeremy Fitzhardinge <jeremy@goop.org>
  * Short circuit GET on ETags match
  
  When client does a conditional GET/HEAD with If-none-match:, if the
  condition fails (ie, the client's ETag matches the file's) then we can
  short-circuit the whole process and immediately return an empty body.

New patches:

[Short circuit GET on ETags match
Jeremy Fitzhardinge <jeremy@goop.org>**20100312001811
 Ignore-this: 79d8f088558390001d5ba6c9a2d17bb3
 
 When client does a conditional GET/HEAD with If-none-match:, if the
 condition fails (ie, the client's ETag matches the file's) then we can
 short-circuit the whole process and immediately return an empty body.
] {
hunk ./src/allmydata/web/filenode.py 363
         contentsize = filesize
         req.setHeader("accept-ranges", "bytes")
         if not self.filenode.is_mutable():
-            # TODO: look more closely at Request.setETag and how it interacts
-            # with a conditional "if-etag-equals" request, I think this may
-            # need to occur after the setResponseCode below
+            # if the client already has the ETag then we can
+            # short-circuit the whole process.
             si = self.filenode.get_storage_index()
hunk ./src/allmydata/web/filenode.py 366
-            if si:
-                req.setETag(base32.b2a(si))
+            if si and req.setETag(base32.b2a(si)):
+                return ""
+
         # TODO: for mutable files, use the roothash. For LIT, hash the data.
         # or maybe just use the URI for CHK and LIT.
         rangeheader = req.getHeader('range')
}

Context:

[setup: add licensing declaration for setuptools (noticed by the FSF compliance folks)
zooko@zooko.com**20100309184415
 Ignore-this: 2dfa7d812d65fec7c72ddbf0de609ccb
] 
[setup: fix error in licensing declaration from Shawn Willden, as noted by the FSF compliance division
zooko@zooko.com**20100309163736
 Ignore-this: c0623d27e469799d86cabf67921a13f8
] 
[CREDITS to Jacob Appelbaum
zooko@zooko.com**20100304015616
 Ignore-this: 70db493abbc23968fcc8db93f386ea54
] 
[desert-island-build-with-proper-versions
jacob@appelbaum.net**20100304013858] 
[docs: a few small edits to try to guide newcomers through the docs
zooko@zooko.com**20100303231902
 Ignore-this: a6aab44f5bf5ad97ea73e6976bc4042d
 These edits were suggested by my watching over Jake Appelbaum's shoulder as he completely ignored/skipped/missed install.html and also as he decided that debian.txt wouldn't help him with basic installation. Then I threw in a few docs edits that have been sitting around in my sandbox asking to be committed for months.
] 
[TAG allmydata-tahoe-1.6.1
david-sarah@jacaranda.org**20100228062314
 Ignore-this: eb5f03ada8ea953ee7780e7fe068539
] 
Patch bundle hash:
0d730c29b79e7708178bef2bb01a55fc29949a4d