Abstract error handling in python code

Signed-off-by: jwijenbergh <jeroenwijenbergh@protonmail.com>

2 files changed, 42 insertions, 27 deletions

diff --git a/src/server.go b/src/server.go
index e39f4c7..7fe3735 100644
--- a/src/server.go
+++ b/src/server.go
@@ -1,9 +1,9 @@
 package eduvpn
 
 import (
+	"fmt"
 	"io/ioutil"
 	"net/http"
-	"fmt"
 )
 
 func getFileUrl(url string) ([]byte, error) {
@@ -24,7 +24,7 @@ func getFileUrl(url string) ([]byte, error) {
 	if readErr != nil {
 		return nil, detailedVPNError{errRequestFileReadError, fmt.Sprintf("error reading body from file url %s", url), readErr}
 	}
-	return body, nil 
+	return body, nil
 }
 
 // Helper function that gets a disco json
@@ -64,7 +64,7 @@ func getDiscoFile(jsonFile string) (string, error) {
 func GetOrganizationsList() (string, error) {
 	body, err := getDiscoFile("organization_list.json")
 	if err != nil {
-		return "", err.(detailedRequestError).ToVerifyError()
+		return "", err.(detailedRequestError).ToRequestError()
 	}
 	return body, nil
 }
@@ -77,6 +77,7 @@ func GetServersList() (string, error) {
 // RequestErrorCode Simplified error code for public interface.
 type RequestErrorCode = VPNErrorCode
 type RequestError = VPNError
+
 // detailedRequestErrorCode used for unit tests.
 type detailedRequestErrorCode = detailedVPNErrorCode
 type detailedRequestError = detailedVPNError
@@ -103,7 +104,6 @@ func (code detailedRequestErrorCode) ToRequestErrorCode() RequestErrorCode {
 	case errRequestFileReadError:
 	case errRequestFileHTTPError:
 		return ErrRequestFileError
-		return ErrRequestFileError
 	case errVerifySigError:
 		return ErrVerifySigError
 	}
diff --git a/wrappers/python/eduvpncommon/discovery.py b/wrappers/python/eduvpncommon/discovery.py
index d7fa73b..ae721c7 100644
--- a/wrappers/python/eduvpncommon/discovery.py
+++ b/wrappers/python/eduvpncommon/discovery.py
@@ -10,22 +10,49 @@ lib.FreeString.argtypes, lib.FreeString.restype = [c_void_p], None
 lib.Verify.argtypes, lib.Verify.restype = [GoSlice, GoSlice, GoSlice, c_uint64], c_int64
 lib.InsecureTestingSetExtraKey.argtypes, lib.InsecureTestingSetExtraKey.restype = [GoSlice], None
 
-class RequestErrorCode(Enum):
-    ErrRequestFileError = 1  # The request for the file has failed.
-    ErrVerifySigError = 2  # The signature failed to verify.
-    Unknown = -1  # Other unknown error.
-
-def getOrganizationsList():
+def getOrganizationsList() -> str:
     dataError = lib.GetOrganizationsList()
     ptr = dataError.data
-    err = dataError.error
+    error = dataError.error
     body = None
-    if not err:
+    if not error:
         body = cast(ptr, c_char_p).value
     lib.FreeString(ptr)
+    if error:
+        raise RequestError(error)
     return body
 
 
+class GoError(Exception):
+    message_dict: Enum
+    code: int
+
+    def __init__(self, err: Enum, messages: dict):
+        assert err
+        try:
+            self.code = err
+        except ValueError:
+            self.code = -1
+        self.message_dict = messages
+
+    def __str__(self):
+        return self.message_dict[self.code] if self.code in self.message_dict else f"unknown error ({self.code})"
+
+
+class RequestErrorCode(Enum):
+    ErrRequestFileError = 1  # The request for the file has failed.
+    ErrVerifySigError = 2  # The signature failed to verify.
+    Unknown = -1  # Other unknown error.
+
+class RequestError(GoError):
+    def __init__(self, err: int):
+        super().__init__(RequestErrorCode(err),
+            {
+                RequestErrorCode.ErrRequestFileError: "file request error",
+                RequestErrorCode.ErrVerifySigError: "signature verify error",
+            })
+
+
 class VerifyErrorCode(Enum):
     ErrUnknownExpectedFileName = 1  # Unknown expected file name specified. The signature has not been verified.
     ErrInvalidSignature = 2  # Signature is invalid (for the expected file type).
@@ -33,27 +60,15 @@ class VerifyErrorCode(Enum):
     ErrTooOld = 4  # Signature timestamp smaller than specified minimum signing time (rollback).
     Unknown = -1  # Other unknown error.
 
-
-class VerifyError(Exception):
-    code: VerifyErrorCode
-    code_int: int  # Original error code also for VerifyErrorCode.Unknown
-
+class VerifyError(GoError):
     def __init__(self, err: int):
-        assert err
-        try:
-            self.code = VerifyErrorCode(err)
-        except ValueError:
-            self.code = VerifyErrorCode.Unknown
-        self.code_int = err
-
-    def __str__(self):
-        return \
+        super().__init__(VerifyErrorCode(err),
             {
                 VerifyErrorCode.ErrUnknownExpectedFileName: "unknown expected file name",
                 VerifyErrorCode.ErrInvalidSignature: "invalid signature",
                 VerifyErrorCode.ErrInvalidSignatureUnknownKey: "invalid signature (unknown key)",
                 VerifyErrorCode.ErrTooOld: "replay of previous signature (rollback)",
-            }[self.code] if self.code != VerifyErrorCode.Unknown else f"unknown verify error ({self.code_int})"
+            })
 
 
 def verify(signature: bytes, signed_json: bytes, expected_file_name: str, min_sign_time: int) -> None: