BUG: ENH: update spa_files to patch timezone bug

pvlib/spa_c_files/README.md

@@ -1,34 +1,38 @@
 README
 ------
 
-NREL provides a C implementation of the solar position algorithm 
-described in 
-[Reda, I.; Andreas, A. (2003). Solar Position Algorithm for Solar Radiation Applications. 55 pp.; NREL Report No. TP-560-34302](
-http://www.nrel.gov/docs/fy08osti/34302.pdf).
+NREL provides a C implementation of the solar position algorithm described in
+[Reda, I.; Andreas, A. (2003). Solar Position Algorithm for Solar Radiation Applications. 55 pp.; NREL Report No. TP-560-34302](http://www.nrel.gov/docs/fy08osti/34302.pdf).
 
 This folder contains the files required to make NREL's C code accessible
 to the ``pvlib-python`` package. We use the Cython package to wrap NREL's SPA 
 implementation. 
 
-** Due to licensing issues, you must download the NREL C files from their 
-[website](http://www.nrel.gov/midc/spa) **
-
-Download the ``spa.c`` and ``spa.h`` files from NREL, 
-and copy them into the ``pvlib/spa_c_files`` directory. 
+** Due to licensing issues, the [SPA C files](http://www.nrel.gov/midc/spa) can
+_not_ be included in the pvlib-python distribution. The SPA C files will be
+downloaded when you build the Python extension. By using this module you agree
+to the NREL license in SPA_NOTICE. **
 
 There are a total of 5 files needed to compile the C code, described below:
 
 * ``spa.c``: original C code from NREL 
 * ``spa.h``: header file for spa.c
-* ``cspa_py.pxd``: a cython header file which essentially tells cython which parts of the main header file to pay attention to
-* ``spa_py.pyx``: the cython code used to define both functions in the python namespace. NOTE: It is possible to provide user access to other paramters of the SPA algorithm through modifying this file 
+* ``cspa_py.pxd``: a cython header file which essentially tells cython which
+  parts of the main header file to pay attention to
+* ``spa_py.pyx``: the cython code used to define both functions in the python
+  namespace. NOTE: It is possible to provide user access to other paramters of
+  the SPA algorithm through modifying this file 
 * ``setup.py``: a distutils file which performs the compiling of the cython code
 
 The cython compilation process produces two files:
 * ``spa_py.c``: an intermediate cython c file
-* ``spa_py.so``: the python module which can be imported into a namespace
+* ``spa_py.so`` or ``spa_py.<cpyver-platform>.pyd``: the python module which
+  can be imported into a namespace
+
+To create the SPA Python extension, use the following shell command inside this
+folder:
+
+    $ python setup.py build_ext --inplace
 
-To process the original 5 files, 
-use the following shell command inside this folder
-
- $ python setup.py build_ext --inplace
+Executing the build command will also download the ``spa.c`` and ``spa.h``
+files from NREL and copy them into the ``pvlib/spa_c_files`` directory.

pvlib/spa_c_files/cspa_py.pxd

@@ -1,40 +1,40 @@
 cdef extern from "spa.h":
-	ctypedef struct spa_data:
-		int year           
-		int month          
-		int day            
-		int hour           
-		int minute         
-		double second  
-		double delta_ut1   
-		double delta_t     
-		double timezone    
-		double longitude   
-		double latitude        
+    ctypedef struct spa_data:
+        int year
+        int month
+        int day
+        int hour
+        int minute
+        double second
+        double delta_ut1
+        double delta_t
+        double time_zone
+        double longitude
+        double latitude
 
-		double elevation       
+        double elevation
 
-		double pressure        
+        double pressure
 
-		double temperature     
+        double temperature
 
-		double slope           
+        double slope
 
-		double azm_rotation        
+        double azm_rotation
 
-		double atmos_refract    
+        double atmos_refract
 
-		int function       
+        int function
 
-		double e0
-		double e
-		double zenith     
-		double azimuth_astro
-		double azimuth    
-		double incidence  
+        double e0
+        double e
+        double zenith
+        double azimuth_astro
+        double azimuth
+        double incidence
 
-		double suntransit 
-		double sunrise    
-		double sunset   
+        double suntransit
+        double sunrise
+        double sunset
 
-	int spa_calculate(spa_data *spa)
+    int spa_calculate(spa_data *spa)

pvlib/spa_c_files/setup.py

@@ -1,9 +1,36 @@
-#setup.py
+# setup.py
 
+import os
+from urllib import request, parse
 from distutils.core import setup
 from distutils.extension import Extension
 from Cython.Build import cythonize
 
+DIRNAME = os.path.dirname(__file__)
+SPA_C_URL = r'https://midcdmz.nrel.gov/apps/download.pl'
+SPA_H_URL = r'https://midcdmz.nrel.gov/spa/spa.h'
+VALUES = {
+    'name': 'pvlib-python',
+    'country': 'US',
+    'company': 'Individual',
+    'software': 'SPA'
+}
+DATA = parse.urlencode(VALUES).encode('ascii')
+
+# get spa.c
+REQ = request.Request(SPA_C_URL, DATA)
+with request.urlopen(REQ) as response:
+    SPA_C = response.read()
+SPA_C = SPA_C.replace(b'timezone', b'time_zone')
+with open(os.path.join(DIRNAME, 'spa.c'), 'wb') as f:
+    f.write(SPA_C)
+# get spa.h
+with request.urlopen(SPA_H_URL) as response:
+    SPA_H = response.read()
+SPA_H = SPA_H.replace(b'timezone', b'time_zone')
+with open(os.path.join(DIRNAME, 'spa.h'), 'wb') as f:
+    f.write(SPA_H)
+
 setup(
-    ext_modules = cythonize([Extension("spa_py", ["spa_py.pyx",'spa.c'])])
+    ext_modules=cythonize([Extension('spa_py', ['spa_py.pyx', 'spa.c'])])
 )