We were finally successful in moving the input loop

to the lower I/O layer.
This means we unified the loop with it's implicit abort
condition (end of stream or ^C).

i3pystatus/__init__.py

@@ -39,40 +39,56 @@ class IOHandler:
         self.inp = inp
         self.out = out
 
-    def write(self, message):
+    def write_line(self, message):
         """Unbuffered printing to stdout."""
 
         self.out.write(message + "\n")
         self.out.flush()
 
     def read(self):
-        """Interrupted respecting reader for stdin."""
+        """Iterate over all input lines (Generator)"""
+
+        while True:
+            try:
+                yield self.read_line()
+            except EOFError:
+                return
+
+    def read_line(self):
+        """Interrupted respecting reader for stdin.
+
+        Raises EOFError if the end of stream has been reached"""
 
-        # try reading a line, removing any extra whitespace
         try:
             line = self.inp.readline().decode("utf-8").strip()
-            # i3status sends EOF, or an empty line
-            if not line:
-                sys.exit(3)
-            return line
-        # exit on ctrl-c
         except KeyboardInterrupt:
-            sys.exit()
+            raise EOFError()
+
+        # i3status sends EOF, or an empty line
+        if not line:
+            raise EOFError()
+        return line
 
 class JSONIO:
     def __init__(self, io):
         self.io = io
-        self.io.write(self.io.read())
-        self.io.write(self.io.read())
+        self.io.write_line(self.io.read_line())
+        self.io.write_line(self.io.read_line())
 
     def read(self):
-        while True:
-            with self.read_line() as j:
+        """Iterate over all JSON input (Generator)"""
+
+        for line in self.io.read():
+            with self.parse_line(line) as j:
                 yield j
 
     @contextmanager
-    def read_line(self):
-        line, prefix = self.io.read(), ""
+    def parse_line(self, line):
+        """Parse a single line of JSON and write modified JSON back.
+
+        Usage is quite simple using the usual with-Syntax."""
+
+        prefix = ""
 
         # ignore comma at start of lines
         if line.startswith(","):
@@ -80,7 +96,7 @@ class JSONIO:
 
         j = json.loads(line)
         yield j
-        self.io.write(prefix + json.dumps(j))
+        self.io.write_line(prefix + json.dumps(j))
 
 class I3statusHandler:
     modules = []
@@ -99,6 +115,6 @@ class I3statusHandler:
         module.registered(self)
 
     def run(self):
-        for j in  self.io.read():
+        for j in self.io.read():
             for module in self.modules:
                 j.insert(module.position, module.output)