ch20: renamed directory

20-executors/getflags/flags2_sequential.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+
+"""Download flags of countries (with error handling).
+
+Sequential version
+
+Sample run::
+
+    $ python3 flags2_sequential.py -s DELAY b
+    DELAY site: http://localhost:8002/flags
+    Searching for 26 flags: from BA to BZ
+    1 concurrent connection will be used.
+    --------------------
+    17 flags downloaded.
+    9 not found.
+    Elapsed time: 13.36s
+
+"""
+
+# tag::FLAGS2_BASIC_HTTP_FUNCTIONS[]
+from collections import Counter
+from http import HTTPStatus
+
+import httpx
+import tqdm  # type: ignore  # <1>
+
+from flags2_common import main, save_flag, DownloadStatus  # <2>
+
+DEFAULT_CONCUR_REQ = 1
+MAX_CONCUR_REQ = 1
+
+def get_flag(base_url: str, cc: str) -> bytes:
+    url = f'{base_url}/{cc}/{cc}.gif'.lower()
+    resp = httpx.get(url, timeout=3.1, follow_redirects=True)
+    resp.raise_for_status()  # <3>
+    return resp.content
+
+def download_one(cc: str, base_url: str, verbose: bool = False) -> DownloadStatus:
+    try:
+        image = get_flag(base_url, cc)
+    except httpx.HTTPStatusError as exc:  # <4>
+        res = exc.response
+        if res.status_code == HTTPStatus.NOT_FOUND:
+            status = DownloadStatus.NOT_FOUND  # <5>
+            msg = f'not found: {res.url}'
+        else:
+            raise  # <6>
+    else:
+        save_flag(image, f'{cc}.gif')
+        status = DownloadStatus.OK
+        msg = 'OK'
+
+    if verbose:  # <7>
+        print(cc, msg)
+
+    return status
+# end::FLAGS2_BASIC_HTTP_FUNCTIONS[]
+
+# tag::FLAGS2_DOWNLOAD_MANY_SEQUENTIAL[]
+def download_many(cc_list: list[str],
+                  base_url: str,
+                  verbose: bool,
+                  _unused_concur_req: int) -> Counter[DownloadStatus]:
+    counter: Counter[DownloadStatus] = Counter()  # <1>
+    cc_iter = sorted(cc_list)  # <2>
+    if not verbose:
+        cc_iter = tqdm.tqdm(cc_iter)  # <3>
+    for cc in cc_iter:
+        try:
+            status = download_one(cc, base_url, verbose)  # <4>
+        except httpx.HTTPStatusError as exc:  # <5>
+            error_msg = 'HTTP error {resp.status_code} - {resp.reason_phrase}'
+            error_msg = error_msg.format(resp=exc.response)
+        except httpx.RequestError as exc:  # <6>
+            error_msg = f'{exc} {type(exc)}'.strip()
+        except KeyboardInterrupt:  # <7>
+            break
+        else:  # <8>
+            error_msg = ''
+
+        if error_msg:
+            status = DownloadStatus.ERROR  # <9>
+        counter[status] += 1           # <10>
+        if verbose and error_msg:      # <11>
+            print(f'{cc} error: {error_msg}')
+
+    return counter  # <12>
+# end::FLAGS2_DOWNLOAD_MANY_SEQUENTIAL[]
+
+if __name__ == '__main__':
+    main(download_many, DEFAULT_CONCUR_REQ, MAX_CONCUR_REQ)