June 2001
Intermediate to advanced
320 pages
9h 18m
English
Content preview from Web Caching
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An Example
If you find yourself in the position of implementing Cache Digests, you can use the following two tables to verify your code. Table E-2 shows three sample URIs and their MD5 hash values. Table E-3 lists the same three URIs with the bit positions for four hash functions based on the MD5 column in Table E-2. This example uses a MASK_SIZE of 625,000 bytes, or 5,000,000 bits.
Table E-2. Cache Digest Example: URIs and Hash Values
| Method | URI | MD5 |
|---|---|---|
| GET | http://www.squid-cache.org | 69677C33244C8D776D1ED1210E07C120 |
| GET | http://www.oreilly.com | 4DC8FAFB9B5B0A4C08D992E453059333 |
| GET | ftp://ftp.ircache.net | F36FB917F5D687629A6E2BEB6BB569FF |
Table E-3. Cache Digest Example: URIs and Bit Positions
| Method | URI | B1 | B2 | B3 | B4 |
|---|---|---|---|---|---|
| GET | http://www.squid-cache.org | 3,389,683 | 3,996,727 | 736,161 | 389,216 |
| GET | http://www.oreilly.com | 17,083 | 1,434,892 | 3,476,644 | 2,874,291 |
| GET | ftp://ftp.ircache.net | 4,185,367 | 4,477,282 | 911,467 | 2,051,263 |