how to use "AND", "OR" for RewriteCond on Apache?

Is this how to use AND, OR for RewriteCond on Apache?

rewritecond A [or]
rewritecond B
rewritecond C [or]
rewritecond D
RewriteRule ... something

becomes if ( (A or B) and (C or D) ) rewrite_it.

So it seems like "OR" is higher precedence than "AND"? Is there a way to easily tell, like in the (A or B) and (C or D) syntax?

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小开

This is an interesting question and since it isn't explained very explicitly in the documentation I'll answer this by going through the sourcecode of mod_rewrite; demonstrating a big benefit of open-source.

In the top section you'll quickly spot the defines used to name these flags:

#define CONDFLAG_NONE               1<<0
#define CONDFLAG_NOCASE             1<<1
#define CONDFLAG_NOTMATCH           1<<2
#define CONDFLAG_ORNEXT             1<<3
#define CONDFLAG_NOVARY             1<<4

and searching for CONDFLAG_ORNEXT confirms that it is used based on the existence of the [OR] flag:

else if (   strcasecmp(key, "ornext") == 0
|| strcasecmp(key, "OR") == 0    ) {
cfg->flags |= CONDFLAG_ORNEXT;
}

The next occurrence of the flag is the actual implementation where you'll find the loop that goes through all the RewriteConditions a RewriteRule has, and what it basically does is (stripped, comments added for clarity):

# loop through all Conditions that precede this Rule
for (i = 0; i < rewriteconds->nelts; ++i) {
rewritecond_entry *c = &conds[i];


# execute the current Condition, see if it matches
rc = apply_rewrite_cond(c, ctx);


# does this Condition have an 'OR' flag?
if (c->flags & CONDFLAG_ORNEXT) {
if (!rc) {
/* One condition is false, but another can be still true. */
continue;
}
else {
/* skip the rest of the chained OR conditions */
while (   i < rewriteconds->nelts
&& c->flags & CONDFLAG_ORNEXT) {
c = &conds[++i];
}
}
}
else if (!rc) {
return 0;
}
}

You should be able to interpret this; it means that OR has a higher precedence, and your example indeed leads to if ( (A OR B) AND (C OR D) ). If you would, for example, have these Conditions:

RewriteCond A [or]
RewriteCond B [or]
RewriteCond C
RewriteCond D

it would be interpreted as if ( (A OR B OR C) and D ).

小开

After many struggles and to achive a general, flexible and more readable solution, in my case I ended up saving the ORs results into ENV variables and doing the ANDs of those variables.

# RESULT_ONE = A OR B
RewriteRule ^ - [E=RESULT_ONE:False]
RewriteCond ...A... [OR]
RewriteCond ...B...
RewriteRule ^ - [E=RESULT_ONE:True]


# RESULT_TWO = C OR D
RewriteRule ^ - [E=RESULT_TWO:False]
RewriteCond ...C... [OR]
RewriteCond ...D...
RewriteRule ^ - [E=RESULT_TWO:True]


# if ( RESULT_ONE AND RESULT_TWO ) then ( RewriteRule ...something... )
RewriteCond %{ENV:RESULT_ONE} =True
RewriteCond %{ENV:RESULT_TWO} =True
RewriteRule ...something...

Requirements:


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