(E/m)^-2 =

One requirement of the OAuth spec is the "Lexicographical Byte Value Ordering" of request parameters. The term Lexicographical is misleading as it implies a form of case-insensitive dictionary sorting whereas in practice, the spec implements an Ordinal sort. Specifically and more simply put -all the spec requires is sorting by ASCII character value. In case two parameters share the same name, then the ordering convention applies to both the parameter's name and value -i.e., concatenate key+value before sorting and call it a day.

To keep things simple, I found that expanding the parameter key/value pairs into strings of ASCII codes represented in hexadecimal format allows a simple asort($myByteArray, SORT_STRING) PHP builtin function to do the trick.

Pass in a delimited string of key=value pairs and this function will return a string with the parameters urlencoded, sorted Ordinally by ASCII values as per the OAuth spec:




Params in:
Msg=Hello World!, MSg=Hello World!, 1=one ,za=1, a= 2>1, B= 2 , c= hi there,f=50, f=25 , f=a, test=z, test=z1, test=z12, test=

Outputs:

1=one&B=2&MSg=Hello World!&Msg=Hello World!&a=2>1&c=hi there&f=25&f=a&f=50&test=&test=z12&test=z&test=z1&za=1


(Actual output with urlencoding)

1=one&B=2&MSg=Hello%20World%21&Msg=Hello%20World%21&a=2%3E1&c=hi%20there&f=25&f=a&f=50&test=&test=z12&test=z&test=z1&za=1