add feature detection

owrx/config.py

@@ -1,3 +1,5 @@
+import os
+
 class Property(object):
     def __init__(self, value = None):
         self.value = value
@@ -32,3 +34,21 @@ class PropertyManager(object):
 
     def getPropertyValue(self, name):
         return self.getProperty(name).getValue()
+
+class RequirementMissingException(Exception):
+    pass
+
+class FeatureDetector(object):
+    def detectAllFeatures(self):
+        print("Starting Feature detection")
+        self.detect_csdr()
+        self.detect_nmux()
+        print("Feature detection completed.")
+
+    def detect_csdr(self):
+        if os.system("csdr 2> /dev/null") == 32512: #check for csdr
+            raise RequirementMissingException("You need to install \"csdr\" to run OpenWebRX!")
+
+    def detect_nmux(self):
+        if os.system("nmux --help 2> /dev/null") == 32512: #check for nmux
+            raise RequirementMissingException("You need to install an up-to-date version of \"csdr\" that contains the \"nmux\" tool to run OpenWebRX! Please upgrade \"csdr\"!")

server.py

@@ -1,23 +1,40 @@
 from http.server import HTTPServer
 from owrx.http import RequestHandler
-from owrx.config import PropertyManager
-from owrx.source import RtlNmuxSource, SpectrumThread
+from owrx.config import PropertyManager, FeatureDetector, RequirementMissingException
+from owrx.source import RtlNmuxSource
 from socketserver import ThreadingMixIn
 
 class ThreadedHttpServer(ThreadingMixIn, HTTPServer):
     pass
 
 def main():
+    print()
+    print("OpenWebRX - Open Source SDR Web App for Everyone!  | for license see LICENSE file in the package")
+    print("_________________________________________________________________________________________________")
+    print()
+    print("Author contact info:    Andras Retzler, HA7ILM <randras@sdr.hu>")
+    print()
+
     cfg=__import__("config_webrx")
     pm = PropertyManager.getSharedInstance()
     for name, value in cfg.__dict__.items():
         if (name.startswith("__")): continue
         pm.getProperty(name).setValue(value)
 
+    try:
+        FeatureDetector().detectAllFeatures()
+
+    except RequirementMissingException as e:
+        print("you are missing required dependencies to run openwebrx. "
+              "please check the message and the readme for details:")
+        print(e)
+        return
+
     RtlNmuxSource()
 
     server = ThreadedHttpServer(('0.0.0.0', pm.getPropertyValue("web_port")), RequestHandler)
     server.serve_forever()
 
+
 if __name__=="__main__":
     main()