New post

content/blog/python-refactoring-exceptions-context-manager.md

@@ -0,0 +1,88 @@
+---
+title: "Quick Python: Refactoring Exceptions with Context Manager"
+date: 2024-02-01T20:48:21-05:00
+draft: false
+tags: ["Python"]
+math: false
+medium_enabled: false
+---
+
+I generally find exception syntax a little clunky...
+
+```python
+try:
+    for _ in range(5):
+        sleep(1)
+except KeyboardInterrupt:
+    # Awesome task 1
+    # Awesome task 2...
+    pass
+```
+
+Especially if you end up capturing the same exceptions and handling it the same way.
+
+```python
+try:
+    for _ in range(5):
+        sleep(1)
+except KeyboardInterrupt:
+    # Awesome task 1
+    # Awesome task 2...
+    pass
+
+try:
+    for _ in range(2):
+        sleep(1)
+except KeyboardInterrupt:
+    # Awesome task 1
+    # Awesome task 2...
+    pass
+```
+
+One way to make our code more DRY (don't-repeat-yourself) is to make use of Python's context managers.
+
+```python
+@contextmanager
+def handle_sigint():
+    try:
+        yield
+    except KeyboardInterrupt:
+        # Awesome task 1
+        # Awesome task 2...
+        pass
+```
+
+Using the context manager, everything within the indented block gets executed within the try block.
+
+```python
+with handle_sigint():
+    for _ in range(5):
+        sleep(1)
+
+with handle_sigint():
+    for _ in range(2):
+        sleep(1)
+```
+
+In fact, we can write this in a generic way to give us an alternative syntax for handling exceptions.
+
+```python
+@contextmanager
+def handle_exception(f, *exceptions):
+    try:
+        yield
+    except exceptions as e:
+        f(e)
+```
+
+For example, let's tell the user that we're explicitly ignoring their exception
+
+```python
+def ignore(e):
+    print("Ignoring", e.__class__.__name__)
+
+with handle_exception(ignore, NotImplementedError, KeyboardInterrupt):
+    for _ in range(5):
+        sleep(1)
+```
+