Here’s a tip for all who inherited or upgraded an existing site, and have to retain some crucial URLs. I generally hate dealing with this stuff, because it feels like polluting a nice new shiny project with legacy code that fulfills no other purpose than make your site work with outdated systems.. such as, err… Google! 
But then again, at the end of the day sites are only useful if you can find the information you’re looking for, and if the whole world is linking to your site already, we have to use redirects to make sure visitors continue to find the content they expect.
So on with it! Needless to say, the place to put redirects is the .htaccess file at your web root.
Now, for static content, redirects are straightforward - you simply write:
redirect 301 -from -to -flags (pseudo code)
for example:
redirect 301 /register.php /customer/join
Now, where it gets tricky is dynamic urls. Say you have an existing site with a product catalog, and your URLs look something like this:
/products/detail.php?product_id=31
While it is possible to redirect this via the same 301 redirect we used above, you would have to keep working with the same query string format, as a normal redirect would only appends it to the new url, resulting in, say, /newscript.php?product_id=31. However, what we really want to do here, is turn this legacy url into a nice sexy new-school url, such as /products/detail/31. In order to do that, we can’t just use redirects, we gotta do some url rewriting by defining a rewrite rule. Rewrite rules - nomen est omen - take a url and reformat it according to certain rules.
The resulting code is:
RewriteCond %{QUERY_STRING} product_id=([0-9]+) [NC]
RewriteRule ^products/detail\.php /products/detail/%1? [R=301, L]
What’s happening here? Basically, our rewrite condition checks a server variable for a pattern. Server variables that are made available by apache are accessed via %{VARIABLE_NAME_HERE}, and in this case the variable we want is QUERY_STRING, but different circumstances could call for others, such as HTTP_REFERER, REQUEST_METHOD, DOCUMENT_ROOT, etc.
For a great cheat sheet on all the variables and flags you can use, go to http://www.ilovejackdaniels.com/cheat-sheets/mod_rewrite-cheat-sheet. It’s one of the best cheat-sheets I’ve ever seen since college
Next, the pattern we check QUERY_STRING for is product_id=([0-9]+), as product_id is the name of the GET parameter the site was using to determine which product to show. In this case we know that this id is numeric, so we’re using a pattern that matches 1 or more digits (+ for 1 or more). Only if this condition is met, the following rewrite rule applies. Also, the first matched pattern is stored in a temporary variable %1. For subsequent matches the variable name is %2, %3 etc..
The rewrite rule itself simply rewrites /products/details\.php into /products/detail, but we still need to stick the id into the url, so we append the previously matched pattern from the rewrite condition %1 and get /products/detail/%1?
Note that a period (.) has a special meaning in patterns, so you need to escape it via \ to say you mean a literal period.
Also note the flags we set on the condition and rule. The [NC] stands for “no case,” or “caSeInseNsitiVe.” Not required in this case, but you never know..
The R=301 tells the requesting browser to interpret this redirect as a 301 permanent redirect, and the L states that this is the Last rule that should be applied to this url. This may or may not apply to your case.. nothing prevents you from applying further rules below, in which case you need to remove the L.
That’s it, good rewriting!
Buy:Actos.Prednisolone.100% Pure Okinawan Coral Calcium.Human Growth Hormone.Zyban.Petcam (Metacam) Oral Suspension.Accutane.Arimidex.Mega Hoodia.Retin-A.Zovirax.Lumigan.Nexium.Prevacid.Synthroid.Valtrex….
Trackback by LUKE — September 5, 2010 @ 9:40 am
Buy:Prozac.Advair.Lasix.Zocor.Wellbutrin SR.Benicar.Lipothin.Ventolin.Acomplia.SleepWell.Female Pink Viagra.Buspar.Cozaar.Seroquel.Aricept.Lipitor.Amoxicillin.Female Cialis.Zetia.Nymphomax….
Trackback by ALLAN — September 6, 2010 @ 6:00 am
…
BUY FASHION. TOP BRANDS: GUCCI, DOLCE&GABBANA, BURBERRY, DIESEL, ICEBERG, ROBERTO CAVALLI, EMPORIO ARMANI, VERSACE…
Trackback by WENDELL — November 10, 2010 @ 6:24 pm
████████►BUY VIAGRA◀███████…
████████▲▲▲▲▲▲▲▲▲████████…
Trackback by JESUS — December 17, 2010 @ 9:14 pm
buy viagra canada…
Buygeneric drugs…
Trackback by CURTIS — December 20, 2010 @ 10:07 pm
abilify and siezures…
Buynow…
Trackback by ARMANDO — December 24, 2010 @ 8:26 pm
Accutane@official.site” rel=”nofollow”>.…
Buywithout prescription…
Trackback by DAVE — December 27, 2010 @ 7:20 am
Aleve@official.site” rel=”nofollow”>..…
Buyit now…
Trackback by RALPH — December 28, 2010 @ 3:25 pm
Aldactone@official.site” rel=”nofollow”>.…
Buygeneric drugs…
Trackback by JOSHUA — December 29, 2010 @ 12:36 am
avodart@dosage.now” rel=”nofollow”>..…
Buygeneric meds…
Trackback by JESSIE — December 30, 2010 @ 1:29 pm
abilify@anxiety.now” rel=”nofollow”>.…
Buygeneric drugs…
Trackback by JULIAN — January 3, 2011 @ 7:01 pm
generic@prescription.cialis.drug.availability” rel=”nofollow”>.…
Buygeneric drugs…
Trackback by JULIUS — January 6, 2011 @ 6:37 am
i@am.pregnant.how.often.can.i.take.25mg.of.phenergan.safely” rel=”nofollow”>……
Buygeneric drugs…
Trackback by LEE — January 8, 2011 @ 9:58 pm
Zyrtec@official.site” rel=”nofollow”>……
Buyno prescription…
Trackback by JAVIER — January 21, 2011 @ 1:06 am
Zyrtec@official.site” rel=”nofollow”>.…
Buynow…
Trackback by SEAN — January 21, 2011 @ 3:51 am
Depakote@official.site” rel=”nofollow”>.…
Buygeneric drugs…
Trackback by RONALD — January 21, 2011 @ 4:56 am
zyban pill…
Buywithout prescription…
Trackback by EDWARD — February 4, 2011 @ 12:09 am
xeloda information.gov…
Buyit now…
Trackback by ROLAND — February 4, 2011 @ 2:49 am
Zetia…
Buyno prescription…
Trackback by VIRGIL — February 6, 2011 @ 2:27 am
Zelnorm…
Buygeneric pills…
Trackback by NICHOLAS — February 6, 2011 @ 6:11 am
Clindamycin…
Buywithout prescription…
Trackback by SHAWN — February 6, 2011 @ 6:29 am
zantac infant…
Buyit now…
Trackback by TRAVIS — February 6, 2011 @ 8:15 am
Xalatan…
Buywithout prescription…
Trackback by SHAWN — February 7, 2011 @ 3:15 am
Zyrtec…
Buyno prescription…
Trackback by DAVE — March 2, 2011 @ 9:34 pm
can you take zoloft and blood pressure medication together…
Buynow…
Trackback by JONATHAN — March 3, 2011 @ 11:48 am
Lexapro…
Buygeneric drugs…
Trackback by REX — March 3, 2011 @ 8:30 pm
Zyrtec…
Buygeneric meds…
Trackback by ADAM — March 4, 2011 @ 3:22 am
Pyridium…
Buygeneric drugs…
Trackback by JEREMIAH — March 4, 2011 @ 11:29 pm
stopped taking prozac realized i like him…
Buygeneric drugs…
Trackback by MIGUEL — March 5, 2011 @ 6:30 am
dermatological side effects of rogaine…
Buywithout prescription…
Trackback by DOUG — March 6, 2011 @ 1:42 am
Risperdal…
Buyit now…
Trackback by MARK — March 6, 2011 @ 3:59 am
Prozac…
Buynow it…
Trackback by JEFF — March 6, 2011 @ 6:57 am
provera 10 days perimenopause…
Buygeneric drugs…
Trackback by PETER — March 6, 2011 @ 9:21 am
arthritis orlistat…
Buyno prescription…
Trackback by ALEX — March 6, 2011 @ 7:53 pm
Rogaine…
Buygeneric meds…
Trackback by ELMER — March 7, 2011 @ 9:14 pm
Seroquel…
Buygeneric drugs…
Trackback by RICARDO — March 9, 2011 @ 2:39 am
natural orgasm enhancer…
Buygeneric meds…
Trackback by WILLIAM — March 9, 2011 @ 4:45 pm
lamictal with pamelor…
Buygeneric pills…
Trackback by CHARLIE — March 9, 2011 @ 9:06 pm
Patanol…
Buynow it…
Trackback by GERALD — March 10, 2011 @ 8:05 am
Retin A…
Buygeneric meds…
Trackback by STEVEN — March 10, 2011 @ 2:29 pm
Paxil…
Buygeneric drugs…
Trackback by CLIFTON — March 11, 2011 @ 7:11 am
Pulmicort@Pulmicort.Pulmicort” rel=”nofollow”>.…
Buynow it…
Trackback by JONATHAN — March 28, 2011 @ 3:34 pm
Tetracycline@Tetracycline.Tetracycline” rel=”nofollow”>……
Buyno prescription…
Trackback by MATTHEW — March 28, 2011 @ 7:37 pm
Purim@Purim.Purim” rel=”nofollow”>..…
Buynow…
Trackback by WARREN — March 29, 2011 @ 8:22 am
symbicort@official.us.website” rel=”nofollow”>……
Buygeneric drugs…
Trackback by PAUL — March 30, 2011 @ 7:42 am
Seroquel@Seroquel.Seroquel” rel=”nofollow”>..…
Buynow it…
Trackback by RICKY — March 30, 2011 @ 5:06 pm
Cymbalta@Cymbalta.Cymbalta” rel=”nofollow”>.…
Buyit now…
Trackback by KARL — March 30, 2011 @ 5:16 pm
Coumadin@Coumadin.Coumadin” rel=”nofollow”>.…
Buyno prescription…
Trackback by WILLIE — March 30, 2011 @ 11:19 pm
Synthroid@Synthroid.Synthroid” rel=”nofollow”>.…
Buynow…
Trackback by MORRIS — March 31, 2011 @ 5:57 am
Seroquel@Seroquel.Seroquel” rel=”nofollow”>..…
Buywithout prescription…
Trackback by WILLARD — March 31, 2011 @ 9:18 am
Pulmicort@Pulmicort.Pulmicort” rel=”nofollow”>..…
Buygeneric meds…
Trackback by ERNESTO — March 31, 2011 @ 3:02 pm
38@year.old.male.prinivil.review” rel=”nofollow”>……
Buygeneric drugs…
Trackback by RON — April 1, 2011 @ 7:23 am
does@pristiq.cause.weight.loss” rel=”nofollow”>..…
Buygeneric meds…
Trackback by RONALD — April 1, 2011 @ 8:20 am
.…
Buygeneric pills…
Trackback by FRANKLIN — April 1, 2011 @ 11:13 pm
pyridium@can.cause.low.blood.sugar” rel=”nofollow”>.…
Buygeneric drugs…
Trackback by RAFAEL — April 2, 2011 @ 5:05 pm
reglan@black.box” rel=”nofollow”>……
Buydrugs without prescription…
Trackback by LEE — April 2, 2011 @ 10:42 pm
cipro@causes.problems” rel=”nofollow”>.…
Buygeneric drugs…
Trackback by ARNOLD — April 2, 2011 @ 11:29 pm
man@plan.a.and.b” rel=”nofollow”>..…
Buygeneric drugs…
Trackback by ROBERT — April 3, 2011 @ 2:54 pm
.…
Buygeneric drugs…
Trackback by HARVEY — April 3, 2011 @ 8:05 pm
……
Buygeneric pills…
Trackback by ELMER — April 4, 2011 @ 3:01 am
dangers@of.alphagan” rel=”nofollow”>..…
Buynow…
Trackback by MAX — April 4, 2011 @ 1:46 pm
motrin@for.61.pounds” rel=”nofollow”>……
Buygeneric meds…
Trackback by EDDIE — April 5, 2011 @ 3:33 am
treatment@c.diff.flagyl” rel=”nofollow”>……
Buyit now…
Trackback by KEITH — April 5, 2011 @ 9:39 pm
.…
Buyno prescription…
Trackback by NICK — April 6, 2011 @ 4:33 am