sön 25 jun 2023 06:41:04 CEST

1 files changed, 56 insertions, 0 deletions

diff --git a/Python Pipeline.wiki b/Python Pipeline.wiki
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+++ b/Python Pipeline.wiki
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+{{{python
+#!/usr/bin/env python3
+
+import base64
+import hashlib
+import os.path
+import sys
+from typing import Callable, Any
+from dataclasses import dataclass
+
+
+@dataclass
+class Pipeline:
+    """
+    A data pipeline.
+
+    "Syntax" to allow functions and methods to be chained, similar to
+    clojures arrow operator (``->``).
+
+    Each operation applies some kind of procedure, and forwards the
+    pipeline with the result (by returning a new Pipeline object with
+    the contained object being replaced:
+
+    ``.do`` applies a function, passing the pipelined object as the
+    first value. If another position is wanted, use a lambda.
+
+    ``.on`` Applies a method on the object. The method name needs to
+    be passed as a string due to how python works.
+    """
+
+    object: Any
+
+    def on(self, proc: str, *args) -> 'Pipeline':
+        """Apply function to pipeline."""
+        return Pipeline(getattr(self.object, proc)(*args))
+
+    def do(self, proc: Callable, *args) -> 'Pipeline':
+        """Run method in pipeline."""
+        return Pipeline(proc(self.object, *args))
+
+
+with open(os.path.expanduser('~/.ssh/id_rsa'), 'rb') as f:
+    data = f.read()
+
+Pipeline(data) \
+    .on('split', b'\n') \
+    .do(lambda x: x[1:-2]) \
+    .do(lambda d: b''.join(d)) \
+    .do(base64.b64decode) \
+    .do(hashlib.sha256) \
+    .on('digest') \
+    .do(base64.b64encode) \
+    .do(sys.stdout.buffer.write)
+
+print()
+}}}