I'm sorry, there was a mistake in my example. The dlopen step should be
used just to check whether the file is accessible as a shared library.
ccall expects the full path to the .dylib file in case the library is not
at a "standard" location.
Do something like this instead:
const liboauth = "/path/to/liboauth"
(dlopen_e(liboauth) == C_NULL) && error("Unable to load shared library
at the given path.")
b64d = ccall((:oauth_sign_hmac_sha1, liboauth), Ptr{Uint8},
(Ptr{Uint8}, Ptr{Uint8}), testurl, testkey)
println(bytestring(b64d))
Note that you have to use bytestring and not string. string will create a
string from printing the pointer (which will show something like Ptr{Uint8}
@0x0000012345). bytestring converts a C string from a pointer to an
ASCIIString, which is what you want.
--
João Felipe Santos
On Mon, Sep 1, 2014 at 4:24 PM, Randy Zwitch <randy.zwi...@fuqua.duke.edu>
wrote:
> Thanks for the suggestions everyone. Unfortunately, neither the code from
> Ivar nor João worked for me.
>
> liboauth = dlopen("/usr/local/lib/liboauth.dylib")
>
> Out[8]:
>
> Ptr{Void} @0x00007fdc665c5ca0
>
> In [9]:
>
> function oauth_sign_hmac_sha1(m::String,k::String)
>
> res =
> ccall((:oauth_sign_hmac_sha1,liboauth),Ptr{Uint8},(Ptr{Uint8},Ptr{Uint8}),m,k)
>
> if res == C_NULL
>
> error("oauth_sign_hmac_sha1 failed")
>
> end
>
> return string(res)
>
> end
>
>
>
> testurl =
> "GET&http%3A%2F%2Fphotos.example.net%2Fphotos&file%3Dvacation.jpg%26oauth_consumer_key%3Ddpf43f3p2l4k3l03%26oauth_nonce%3Dkllo9940pd9333jh%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1191242096%26oauth_token%3Dnnch734d00sl2jdk%26oauth_version%3D1.0%26size%3Doriginal"
>
> testkey = "kd94hf93k423kf44&pfkkdhi9sl3r4s00"
>
> oauth_sign_hmac_sha1(testurl, testkey)
>
> type: oauth_sign_hmac_sha1: in ccall: first argument not a pointer or valid
> constant expression, expected DataType, got Type{(Any...,)}
> while loading In[9], in expression starting on line 11
>
> in oauth_sign_hmac_sha1 at In[9]:2
>
>
>
>
> testurl =
> "GET&http%3A%2F%2Fphotos.example.net%2Fphotos&file%3Dvacation.jpg%26oauth_consumer_key%3Ddpf43f3p2l4k3l03%26oauth_nonce%3Dkllo9940pd9333jh%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1191242096%26oauth_token%3Dnnch734d00sl2jdk%26oauth_version%3D1.0%26size%3Doriginal"
>
> testkey = "kd94hf93k423kf44&pfkkdhi9sl3r4s00"
>
> b64d = ccall((:oauth_sign_hmac_sha1, liboauth), Ptr{Uint8}, (Ptr{Uint8},
> Ptr{Uint8}), testurl, testkey)
>
> bytestring(b64d)
>
> type: anonymous: in ccall: first argument not a pointer or valid constant
> expression, expected DataType, got Type{(Any...,)}
> while loading In[10], in expression starting on line 3
>
> in anonymous at no file
>
>
> Does this mean I compiled the library wrong? When I did the 'make' step,
> after it was complete, I did 'make installcheck' and the 3 tests reported
> that they completed successfully.
>
> At a higher level, I like Isaiah's suggestion of doing this process by
> hand to really get to understanding what is going on. Is there an eaier
> external library that one of you could suggest that I could use to walk
> through the entire process? I've done the examples in the manual using
> :clock and :getenv and understand what is going on, so now I want to work
> with a user-installed library to make sure I really get the process. I
> started with OAuth to see if I could make something usable to work with my
> Twitter package, but maybe it's not the best starting place.
>
>
> On Monday, September 1, 2014 10:47:22 AM UTC-4, João Felipe Santos wrote:
>
>> You need to do ccalls using Ptr{Uint8}. What you can do actually is wrap
>> the Clang.jl-generated functions with your own functions with an
>> alternative signature, and then convert from ASCIIString to Ptr{Uint8}.
>> Note that you probably will need to do it anyways to wrap the return types,
>> since you probably do not want to work with pointers from Julia :)
>>
>> In that specific example, if m and k are ASCIIStrings, conversions will
>> be done automatically:
>>
>> testurl = "GET&http%3A%2F%2Fphotos.example.net%2Fphotos&file%
>> 3Dvacation.jpg%26oauth_consumer_key%3Ddpf43f3p2l4k3l03%26oauth_
>> nonce%3Dkllo9940pd9333jh%26oauth_signature_method%
>> 3DHMAC-SHA1%26oauth_timestamp%3D1191242096%26oauth_token%
>> 3Dnnch734d00sl2jdk%26oauth_version%3D1.0%26size%3Doriginal"
>> testkey = "kd94hf93k423kf44&pfkkdhi9sl3r4s00"
>> b64d = ccall((:oauth_sign_hmac_sha1, liboauth), Ptr{Uint8},
>> (Ptr{Uint8}, Ptr{Uint8}), testurl, testkey)
>>
>> Note that b64d here will be a Ptr{Uint8}, which you can convert to a
>> Julia string by using bytestring(b64d).
>>
>> --
>> João Felipe Santos
>>
>>
>>
