Why does HTTP use only printable characters?

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Why HTTP protocol is designed in plain text way?

To show my complete ignorance of how TCP/IP works: Looking at the ASCII table, what is the rationale of HTTP using only tab, newline and [x20-x7E] for the protocol?

For example, why is "x02" ("Start of Text") not used but a double newline "x0Ax0A"?

Has it to do with any interference with TCP/IP (as in "is not allowed in Application Layer")? Is there perhaps a more trivial reason? Or a more complicated?

Duplicate of this question: Why HTTP protocol is designed in plain text way?.

Probably a duplicate of http://stackoverflow.com/questions/393407/why-http-protocol-is-designed-in-plain-text-way — Eugene Mayevski 'Callback, Jan 31 '11 at 11:04
Yep. Is a duplicate. Thanks for pointing out. (I voted for closing it.) — Boldewyn, Jan 31 '11 at 11:18

score 2 · Answer 1 · answered Jan 31 '11 at 11:03

Text-based protocols are easier to debug - no need for special formatting/decoding routines in your debug print code, just dump the entire request to the console. Likewise, you can make a HTTP request just by typing it into an appropriate generic TCP relay program (eg, netcat).

score 1 · Answer 2 · answered Jan 31 '11 at 11:06

I can't speak as to why HTTP chose to use that particular restricted character set, but it doesn't have to do with the restrictions of TCP/IP. TCP/IP packets are structured more or less like an envelope; they have complex routing and formatting information that must be stored in a very specific format, but the actual contents of the packet payloads can be whatever you choose. The packet headers contain enough information to allow for forwarding and transmission regardless of the packet content.

Why does HTTP use only printable characters?

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