Read data from output

epanet/epanet.py

@@ -13,10 +13,81 @@ def _verify_platform():
         raise Exception(f'Platform {_platform} unsupported (not yet)')
 
 
+class Output:
+    def __init__(self, name: str) -> None:
+        self._name = name
+
+        self._lib = ctypes.CDLL(os.path.join(os.getcwd(), 'epanet-output.dll'))
+
+        self._handle = ctypes.c_void_p()
+        self._check(self._lib.ENR_init(ctypes.byref(self._handle)))
+
+        dir = os.path.dirname(os.getcwd())
+        opt = os.path.join(os.path.join(dir, 'temp'), self._name + '.db.opt')
+        self._check(self._lib.ENR_open(self._handle, ctypes.c_char_p(opt.encode())))
+
+
+    def _check(self, result):
+        if result != 0:
+            msg = ctypes.c_char_p()
+            code = self._lib.ENR_checkError(self._handle, ctypes.byref(msg))
+            assert code == result
+
+            error = f'Failed to read project [{self._name}] output, message [{msg.value.decode()}]'
+
+            self._lib.ENR_free(ctypes.byref(msg))
+
+            raise Exception(error)
+
+
+    def version(self) -> int:
+        v = ctypes.c_int()
+        self._check(self._lib.ENR_getVersion(self._handle, ctypes.byref(v)))
+        return v.value
+
+
+    def net_size(self) -> dict[str, int]:
+        element_count = ctypes.POINTER(ctypes.c_int)()
+        length = ctypes.c_int()
+        self._check(self._lib.ENR_getNetSize(self._handle, ctypes.byref(element_count), ctypes.byref(length)))
+        assert length.value == 5
+        category = ['node', 'tank', 'link', 'pump', 'valve']
+        counts = {}
+        for i in range(length.value):
+            counts[category[i]] = element_count[i]
+        self._lib.ENR_free(ctypes.byref(element_count))
+        return counts
+
+
+    def units(self) -> dict[str, str]:
+        f_us = ['CFS', 'GPM', 'MGD', 'IMGD', 'AFD', 'LPS', 'LPM', 'MLD', 'CMH', 'CMD']
+        p_us = ['PSI', 'MTR', 'KPA']
+        q_us = ['NONE', 'MGL', 'UGL', 'HOURS', 'PRCNT']
+        f, p, q = ctypes.c_int(1), ctypes.c_int(2), ctypes.c_int(3)
+        f_u, p_u, q_u = ctypes.c_int(), ctypes.c_int(), ctypes.c_int()
+        self._check(self._lib.ENR_getUnits(self._handle, f, ctypes.byref(f_u)))
+        self._check(self._lib.ENR_getUnits(self._handle, p, ctypes.byref(p_u)))
+        self._check(self._lib.ENR_getUnits(self._handle, q, ctypes.byref(q_u)))
+        return { 'flow': f_us[f_u.value], 'pressure': p_us[p_u.value], 'quality': q_us[q_u.value] }
+
+
+    def __del__(self):
+        # throw exception in destructor ? :)
+        self._check(self._lib.ENR_close(ctypes.byref(self._handle)))
+
+
+def _read_output(name: str) -> str:
+    opt = Output(name)
+    print(opt.version())
+    print(opt.net_size())
+    print(opt.units())
+    return ''
+
+
 # readable True => json, False => binary output
 def run_project(name: str, readable: bool = True) -> str:
     if not project.have_project(name):
-        raise Exception(f'Not found project {name}')
+        raise Exception(f'Not found project [{name}]')
 
     dir = os.path.dirname(os.getcwd())
 
@@ -32,25 +103,11 @@ def run_project(name: str, readable: bool = True) -> str:
 
     result = os.system(command)
     if result != 0:
-        raise Exception("Failed to run simulation for project {name}")
+        raise Exception("Failed to run simulation for project [{name}]")
 
-    _lib_output = ctypes.CDLL(os.path.join(os.getcwd(), 'epanet-output.dll'))
-
-    handle = ctypes.c_void_p()
-
-    def _check(result):
-        if result != 0:
-            raise Exception(f'Failed to read output {name}')
-
-    _check(_lib_output.ENR_init(ctypes.byref(handle)))
-
-    _check(_lib_output.ENR_open(handle, ctypes.c_char_p(opt.encode())))
-
-    _check(_lib_output.ENR_close(ctypes.byref(handle)))
-
-    return ''
+    return _read_output(name)
 
 
 if __name__ == '__main__':
     _verify_platform()
-    run_project('net3')
+    _read_output('net3')