Thanks Greg. Here's a variation that gives a little more insight.
#lang racket
(require net/url)
(with-handlers ([(lambda (x) #t)
(lambda (x) (printf "Oops!"))])
(purify-port (head-impure-port (string->url
"http://www.racket-lang.org";))) )
I repeatedly run this. In all cases a header string is returned from the
server. Sometimes it's a 505 error. Sometimes it's "HTTP/1.1 400 Bad
Request ..." and that's when I also see the contract violation. However
no exception is ever caught by the with-handlers. Since I can't catch
the exception I guess it is being logged from a separate thread?
As you say, some sort of error message is appropriate, at least from the
server. But the contract violation makes no sense to me. That must be a
bug I think.
On 10/16/2015 10:17 AM, Greg Hendershott wrote:
The URL needs to get split into parts, and the HTTP request will go
"on the wire" as something like:
HEAD <path> HTTP/1.0
Host: www.racket-lang.org
<more headers>
When you have the trailing / it will be:
HEAD / HTTP/1.0
Which makes sense.
When the trailing slash is missing, i.e. "no path", I'm guessing that
http-conn-send! is sending
HEAD HTTP/1.0
The server thinks the path is "HTTP/1.0" and the HTTP/<ver> part is...
missing. The server doesn't think blank is a valid version of HTTP. It
may have a point. :)
TL;DR1: It's probably good form to use the trailing slash in your
URLs, anyway. (What you can type in a browser address bar is a lot
looser than what you can/should use in code.) This will work even
with the currently shipping Racket.
TL;DR2: Jay, http-conn-send! might want to supply "/" when the path is
missing? Or at least something like (error 'http-conn-send! "URL is
missing a path") so it fails more understandably?
On Fri, Oct 16, 2015 at 6:18 AM, Jon Stenerson <jonstener...@comcast.net> wrote:
This works:
(define p (head-impure-port (string->url "http://www.racket-lang.org/";)))
(read-line p)
"HTTP/1.1 200 OK\r"
But, leaving off trailing /, I usually see
(define p (head-impure-port (string->url "http://www.racket-lang.org";)))
string-trim: contract violation
expected: string?
given: #<eof>
Sometimes I get a port with status line "HTTP/1.1 505 HTTP Version not
supported\r".
Can anyone explain? Thanks.
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