lessons period 2

period_2/02-sockets/902/Transaction.py

@@ -0,0 +1,88 @@
+from Signature import *
+
+class Tx:
+    inputs = None
+    outputs =None
+    sigs = None
+    reqd = None
+    def __init__(self):
+        self.inputs = []
+        self.outputs = []
+        self.sigs = []
+        self.reqd = []
+
+    def add_input(self, from_addr, amount):
+        self.inputs.append((from_addr, amount))
+
+    def add_output(self, to_addr, amount):
+        self.outputs.append((to_addr, amount))
+
+    def add_reqd(self, addr):
+        self.reqd.append(addr)
+
+    def sign(self, private):
+        message = self.__gather()
+        newsig = sign(message, private)
+        self.sigs.append(newsig)
+               
+    def is_valid(self):
+        total_in = 0
+        total_out = 0
+        message = self.__gather()
+        for addr,amount in self.inputs:
+            found = False
+            for s in self.sigs:
+                if verify(message, s, addr):
+                    found = True
+            if not found:
+                # print ("No good sig found for " + str(message))
+                return False
+            if amount < 0:
+                return False
+            total_in = total_in + amount
+        for addr in self.reqd:
+            found = False
+            for s in self.sigs:
+                if verify(message, s, addr):
+                    found = True
+            if not found:
+                return False
+        for addr,amount in self.outputs:
+            if amount < 0:
+                return False
+            total_out = total_out + amount
+
+        # if total_out > total_in:
+        #     # print("Outputs exceed inputs")
+        #     return False
+        
+        return True
+
+    def __gather(self):
+        data=[]
+        data.append(self.inputs)
+        data.append(self.outputs)
+        data.append(self.reqd)
+        return data
+
+    def __repr__(self):
+
+        repr_str = "INPUTS:\n"
+        for addr, amt in self.inputs:
+            repr_str = repr_str + str(amt) + "from" + str(addr) + "\n"
+
+        repr_str += "OUTPUTS:\n"
+        for addr, amt in self.outputs:
+            repr_str = repr_str + str(amt) + "to" + str(addr) + "\n"
+
+        repr_str += "EXTRA REQUIRED SIGNATURES:\n"     
+        for req_sig in self.reqd:
+            repr_str = repr_str + str(req_sig) + "\n"
+
+        repr_str += "SIGNATURES:\n"     
+        for sig in self.sigs:
+            repr_str = repr_str + str(sig) + "\n"
+
+        repr_str += "END\n"
+        
+        return repr_str