Establish native micro runtime checkpoint

1 files changed, 72 insertions, 0 deletions

diff --git a/prototypes/connections/examples/select-text.py b/prototypes/connections/examples/select-text.py
new file mode 100644
index 0000000..ffaf80b
--- /dev/null
+++ b/prototypes/connections/examples/select-text.py
@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+"""Save a UTF-8 document selection through selection.pure (character indices)."""
+import argparse
+import http.client
+import json
+from pathlib import Path
+import re
+import struct
+from urllib.parse import urlsplit
+
+LIMIT = (2 * 6 + 32) * 32768 + 8192
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('file', type=Path)
+    parser.add_argument('--key', required=True)
+    parser.add_argument('--start', type=int, required=True, help='first Unicode code point, starting at 0')
+    parser.add_argument('--end', type=int, required=True, help='exclusive Unicode code point boundary')
+    parser.add_argument('--revision', type=int, default=0, help='0 creates; otherwise expected stored revision')
+    parser.add_argument('--url', default='http://127.0.0.1:8767')
+    args = parser.parse_args()
+    url = urlsplit(args.url)
+    try:
+        port = url.port or 80
+    except ValueError as error:
+        parser.error(str(error))
+    if (url.scheme != 'http' or url.hostname not in ['localhost', '127.0.0.1'] or
+            url.username is not None or url.password is not None or url.path not in ['', '/'] or
+            url.query or url.fragment):
+        parser.error('use a local HTTP server origin')
+    if not re.fullmatch(r'[A-Za-z0-9_-]{1,64}', args.key) or not 0 <= args.revision <= 2**63 - 1:
+        parser.error('invalid object key or revision')
+    try:
+        with args.file.open('rb') as source:
+            document = source.read(LIMIT - 8 + 1)
+        if len(document) > LIMIT - 8:
+            parser.error('document exceeds the prototype request limit')
+        text = document.decode('utf-8')
+    except (OSError, UnicodeError) as error:
+        parser.error(str(error))
+    if not 0 <= args.start <= args.end <= len(text):
+        parser.error('selection is outside the document')
+    start = len(text[:args.start].encode('utf-8'))
+    selected = text[args.start:args.end].encode('utf-8')
+    # The boundary layout is explicit; storage receives only selected bytes.
+    payload = struct.pack('<II', start, len(selected)) + document
+    headers = {'Content-Type': 'application/octet-stream'}
+    headers['If-None-Match' if args.revision == 0 else 'If-Match'] = (
+        '*' if args.revision == 0 else f'"{args.revision}"')
+    connection = http.client.HTTPConnection(url.hostname, port, timeout=12)
+    try:
+        connection.request('PUT', '/objects/' + args.key, payload, headers)
+        response = connection.getresponse()
+        body = response.read(LIMIT + 1)
+        if response.status != 200:
+            parser.error(f'storage response {response.status}: {response.getheader("X-Pure-Error")}')
+        if body != selected:
+            parser.error('response differs from the selection; check the installed program (write may have occurred)')
+        revision = response.getheader('ETag', '')
+        if not re.fullmatch(r'"[1-9][0-9]*"', revision) or int(revision[1:-1]) > 2**63 - 1:
+            parser.error('response has no valid stored revision (write may have occurred)')
+    except (OSError, http.client.HTTPException) as error:
+        parser.error(f'{error}; storage outcome is unknown if the request was sent')
+    finally:
+        connection.close()
+    print(json.dumps({'revision': revision[1:-1], 'selected': selected.decode('utf-8'),
+                      'stored_bytes': len(selected)}, ensure_ascii=False))
+
+
+if __name__ == '__main__':
+    main()