I'm pretty sure that if you modify the wrapper to
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
ccall will automatically convert strings to a simple data pointer, and
convert the resulting string back.
Depending on whether the oath library supports unicode, you should consider
limiting the signature to ASCIIString
Ivar
kl. 15:55:18 UTC+2 mandag 1. september 2014 skrev Randy Zwitch følgende:
>
> To make it a bit more concrete, the C library has this test function:
>
> testurl = "GET&http%3A%2F%2Fphotos.example.net%2Fphotos&file%3D"
> "vacation.jpg%26oauth_consumer_key%3Ddpf43f3p2l4k3l03%26oauth_nonce"
> "%3Dkllo9940pd9333jh%26oauth_signature_method%3DHMAC-SHA1%26o"
> "auth_timestamp%3D1191242096%26oauth_token%3Dnnch734d00sl2jdk"
> "%26oauth_version%3D1.0%26size%3Doriginal";
> testkey = "kd94hf93k423kf44&pfkkdhi9sl3r4s00";
> b64d = oauth_sign_hmac_sha1(testurl , testkey);
>
> In Julia, I have this generated from Clang.jl:
>
> liboauth = dlopen("/usr/local/lib/liboauth.dylib")
>
> function oauth_sign_hmac_sha1(m::Ptr{Uint8},k::Ptr{Uint8})
>
> ccall((:oauth_sign_hmac_sha1,liboauth),Ptr{Uint8},(Ptr{Uint8},Ptr{Uint8}),m,k)
> end
>
> What modifications do I need to make to the Clang Julia code to run this
> test?
>
>
>
> On Monday, September 1, 2014 8:54:59 AM UTC-4, Randy Zwitch wrote:
>>
>> Thanks for the detailed response João! As it turns out, I didn't have any
>> .dylib files as part of the downloaded code, but I was able to figure out
>> how to compile the code and I believe I've got the library installed
>> locally now.
>>
>> When you reference that most of my Ptr{Uint8} values are really just
>> looking for string inputs, can I modify the Julia function signature to
>> take ::ASCIIString instead? Or is this something where I have the leave the
>> type signatures as they are, but understand what the function is actually
>> looking for from the documentation?
>>
>> On Sunday, August 31, 2014 9:19:21 PM UTC-4, João Felipe Santos wrote:
>>>
>>> Hello Randy,
>>>
>>> the following comes from my experience with ccall and Julia
>>> documentation. Please anyone correct me if I explained any of the internals
>>> wrong!
>>>
>>> The API seems to be really simple so pretty much everything can be done
>>> with standard Julia types. Clang.jl seems to have generated correct code
>>> for it.
>>>
>>> Regarding 2, liboauth.dylib (or .dll, or .so on Linux) has to be loaded
>>> and passed to ccall. You can load it by hand using dlopen, like this:
>>>
>>> liboauth = dlopen("/path/of/liboauth.dylib")
>>>
>>> This will raise an error if the path is not valid. If the library is in
>>> your environment's standard path, you can pass its name to ccall as a
>>> string instead of creating a pointer with dlopen.
>>>
>>> Most of the Ptr{Uint8} you got in the code generated by Clang.jl are
>>> actually mapping char *, which are C strings (ASCII, not Unicode). For
>>> example, let's say you wanted to call puts from libc, which is a function
>>> that gets a string as its argument, prints it to the screen followed by a
>>> newline, and returns the number of printed characters. You could do it like
>>> this:
>>>
>>> ccall((:puts, "libc"), Cint, (Ptr{Uint8},), "Hello, Randy")
>>>
>>> So, you basically can pass your string as the function argument and it
>>> should work. You don't need to pass a pointer, but it's good to know that
>>> your Julia ASCIIString was converted to Ptr{Uint8} internally.
>>>
>>> With this you should be able to call functions, but you still need to be
>>> able to recover their output. The second argument to ccall is the C
>>> function return type, but note that often C functions do not return their
>>> output in the return type, but in a variable which was passed by reference
>>> as one of its arguments. I don't know enough of liboauth to know what's the
>>> case, so you will need to check the documentation. See the sections
>>> http://docs.julialang.org/en/release-0.3/manual/calling-c-and-fortran-code/#accessing-data-through-a-pointer
>>>
>>> and
>>> http://docs.julialang.org/en/release-0.3/manual/calling-c-and-fortran-code/#passing-pointers-for-modifying-inputs
>>>
>>> for more details on that.
>>>
>>> --
>>> João Felipe Santos
>>>
>>>
>>> On Sun, Aug 31, 2014 at 8:17 PM, Randy Zwitch <[email protected]>
>>> wrote:
>>>
>>>> Hi all -
>>>>
>>>> I've been trying to learn more about C and how Julia interacts and
>>>> decided to play around with Clang.jl. I decided I was going to wrap
>>>> liboauth from here:
>>>>
>>>> http://liboauth.sourceforge.net/oauth_8h_source.html
>>>>
>>>> I downloaded the C source, which resided in my OSX Downloads directory.
>>>> Using the following Julia code generated a bunch of output:
>>>>
>>>> [1]:
>>>>
>>>> using Clang.wrap_c
>>>>
>>>> In [2]:
>>>>
>>>> context = wrap_c.init(; output_file="liboauth.jl",
>>>> header_library=x->"liboauth", common_file="liboauth.jl",
>>>> clang_diagnostics=true)
>>>>
>>>> context.options.wrap_structs = true
>>>>
>>>> wrap_c.wrap_c_headers(context,
>>>> ["/Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h"])
>>>>
>>>> WARNING: wrap_c_headers: deprecated
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:112:46: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:138:54: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:138:86: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:315:67: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:315:81: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:320:66: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:320:80: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:519:28: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:532:30: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:670:61: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:688:57: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:715:43: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:717:70: warning:
>>>> type specifier missing, defaults to 'int' [-Wimplicit-int]
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:717:77: warning:
>>>> type specifier missing, defaults to 'int' [-Wimplicit-int]
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:717:77: error:
>>>> redefinition of parameter 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:717:70: note:
>>>> previous declaration is here
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:741:24: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:771:43: error:
>>>> unknown type name 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:773:70: warning:
>>>> type specifier missing, defaults to 'int' [-Wimplicit-int]
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:773:77: warning:
>>>> type specifier missing, defaults to 'int' [-Wimplicit-int]
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:773:77: error:
>>>> redefinition of parameter 'size_t'
>>>> /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h:773:70: note:
>>>> previous declaration is here
>>>>
>>>> WRAPPING HEADER: /Users/randyzwitch/Downloads/liboauth-1.0.3/src/oauth.h
>>>>
>>>> WARNING: Not wrapping MacroInstantiation OA_GCC_VERSION_AT_LEAST
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>> WARNING: Not wrapping MacroInstantiation attribute_deprecated
>>>>
>>>> writing liboauth.jl
>>>>
>>>> Out[2]:
>>>>
>>>> 1-element Array{Any,1}:
>>>> nothing
>>>>
>>>>
>>>>
>>>> Output:
>>>>
>>>>
>>>> const LIBOAUTH_VERSION = "1.0.3"
>>>> const LIBOAUTH_VERSION_MAJOR = 1
>>>> const LIBOAUTH_VERSION_MINOR = 0
>>>> const LIBOAUTH_VERSION_MICRO = 3
>>>> const LIBOAUTH_CUR = 8
>>>> const LIBOAUTH_REV = 7
>>>> const LIBOAUTH_AGE = 8
>>>>
>>>> # Skipping MacroDefinition: OA_GCC_VERSION_AT_LEAST ( x , y ) (
>>>> __GNUC__ > x || __GNUC__ == x && __GNUC_MINOR__ >= y )
>>>> # Skipping MacroDefinition: attribute_deprecated __attribute__ ( (
>>>> deprecated ) )
>>>>
>>>> # begin enum ANONYMOUS_1
>>>> typealias ANONYMOUS_1 Uint32
>>>> const OA_HMAC = (uint32)(0)
>>>> const OA_RSA = (uint32)(1)
>>>> const OA_PLAINTEXT = (uint32)(2)
>>>> # end enum ANONYMOUS_1
>>>>
>>>> # begin enum OAuthMethod
>>>> typealias OAuthMethod Uint32
>>>> const OA_HMAC = (uint32)(0)
>>>> const OA_RSA = (uint32)(1)
>>>> const OA_PLAINTEXT = (uint32)(2)
>>>> # end enum OAuthMethod
>>>> function oauth_sign_hmac_sha1(m::Ptr{Uint8},k::Ptr{Uint8})
>>>>
>>>> ccall((:oauth_sign_hmac_sha1,liboauth),Ptr{Uint8},(Ptr{Uint8},Ptr{Uint8}),m,k)
>>>> end
>>>>
>>>> function
>>>> oauth_sign_hmac_sha1_raw(m::Ptr{Uint8},ml::Cint,k::Ptr{Uint8},kl::Cint)
>>>>
>>>> ccall((:oauth_sign_hmac_sha1_raw,liboauth),Ptr{Uint8},(Ptr{Uint8},Cint,Ptr{Uint8},Cint),m,ml,k,kl)
>>>> end
>>>>
>>>> function oauth_sign_plaintext(m::Ptr{Uint8},k::Ptr{Uint8})
>>>>
>>>> ccall((:oauth_sign_plaintext,liboauth),Ptr{Uint8},(Ptr{Uint8},Ptr{Uint8}),m,k)
>>>> end
>>>>
>>>> function oauth_sign_rsa_sha1(m::Ptr{Uint8},k::Ptr{Uint8})
>>>>
>>>> ccall((:oauth_sign_rsa_sha1,liboauth),Ptr{Uint8},(Ptr{Uint8},Ptr{Uint8}),m,k)
>>>> end
>>>>
>>>> function
>>>> oauth_verify_rsa_sha1(m::Ptr{Uint8},c::Ptr{Uint8},s::Ptr{Uint8})
>>>>
>>>> ccall((:oauth_verify_rsa_sha1,liboauth),Cint,(Ptr{Uint8},Ptr{Uint8},Ptr{Uint8}),m,c,s)
>>>> end
>>>>
>>>> <snip>
>>>>
>>>> My questions are:
>>>>
>>>> 1) Did I do this right? I got back a Julia file full of Julia code with
>>>> ccalls, so it seems like I got back what was expected? There were lots of
>>>> deprecation warnings in Julia however.
>>>> 2) How do I actually start using this code for something? Other than
>>>> unzipping the source code for liboauth, I haven't done anything with the C
>>>> code other than generating the Julia ccalls. How will this Julia code know
>>>> how to reference the original source liboauth.h file?
>>>> 3) The Julia functions are using pointers as input types. Do I
>>>> literally need to pass a pointer, or can I just provide the data type of
>>>> the pointer (say, Uint8)?
>>>>
>>>> So, am I on the right track? What should I be thinking about if I want
>>>> to take the next step in actually trying to use these functions?
>>>>
>>>
>>>
