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How can I check if a URL exists via PHP?
...side.
Waiting for a response might take time and block code execution.
Not all headers returned by get_headers() are well formed.
Use curl (if you can).
Prevent fetching the entire body/content, but only request the headers.
Consider redirecting urls:
Do you want the first code returned?
Or follow a...
to drawRect or not to drawRect (when should one use drawRect/Core Graphics vs subviews/images and wh
...bviews whenever you can. You can be more productive, and take advantage of all the OO mechanisms that should things easier to maintain. Use Core Graphics when you can't get the performance you need out of UIKit, or you know trying to hack together drawing effects in UIKit would be more complicated....
Does MySQL ignore null values on unique constraints?
...
Yes, MySQL allows multiple NULLs in a column with a unique constraint.
CREATE TABLE table1 (x INT NULL UNIQUE);
INSERT table1 VALUES (1);
INSERT table1 VALUES (1); -- Duplicate entry '1' for key 'x'
INSERT table1 VALUES (NULL);
INSER...
Crontab - Run in directory
...t I would like it to execute it from a particular directory so it can find all the files it needs, since the application has a bunch of relative paths.
...
JavaScript hard refresh of current page
...aScript?
Hard refresh means getting a fresh copy of the page AND refresh all the external resources (images, JavaScript, CSS, etc.).
...
How do JavaScript closures work?
...clared outside the function, regardless of when and where the function is called.
If a function was called by a function, which in turn was called by another function, then a chain of references to outer lexical environments is created. This chain is called the scope chain.
In the following code, in...
Why are Python's 'private' methods not actually private?
...
The name scrambling is used to ensure that subclasses don't accidentally override the private methods and attributes of their superclasses. It's not designed to prevent deliberate access from outside.
For example:
>>> class Foo(object):
... def __init__(self):
... self....
Ensuring json keys are lowercase in .NET
...m contract resolver for this. The following contract resolver will convert all keys to lowercase:
public class LowercaseContractResolver : DefaultContractResolver
{
protected override string ResolvePropertyName(string propertyName)
{
return propertyName.ToLower();
}
}
Usage:
...
What's an object file in C?
...t from the compilation phase. It's mostly machine code, but has info that allows a linker to see what symbols are in it as well as symbols it requires in order to work. (For reference, "symbols" are basically names of global objects, functions, etc.)
A linker takes all these object files and comb...
Adding console.log to every function automatically
...there a way to make any function output a console.log statement when it's called by registering a global hook somewhere (that is, without modifying the actual function itself) or via some other means?
...