update python asyncio download

pyPractice/fluent_python/chapter18-2-asyncio.py

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+# BEGIN SPINNER_ASYNCIO
+import asyncio
+import itertools
+
+
+async def spin(msg):  # <1>
+    for char in itertools.cycle('|/-\\'):
+        status = char + ' ' + msg
+        print(status, flush=True, end='\r')
+        try:
+            await asyncio.sleep(.1)  # <2>
+        except asyncio.CancelledError:  # <3>
+            break
+    print(' ' * len(status), end='\r')
+
+
+async def slow_function():  # <4>
+    # pretend waiting a long time for I/O
+    await asyncio.sleep(3)  # <5>
+    return 42
+
+
+async def supervisor():  # <6>
+    spinner = asyncio.create_task(spin('thinking!'))  # <7>
+    print('spinner object:', spinner)  # <8>
+    result = await slow_function()  # <9>
+    spinner.cancel()  # <10>
+    return result
+
+
+def main():
+    result = asyncio.run(supervisor())  # <11>
+    print('Answer:', result)
+
+
+if __name__ == '__main__':
+    main()
+# END SPINNER_ASYNCIO

pyPractice/fluent_python/chapter18-downloadflag.py

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+"""Download flags of countries (with error handling).
+asyncio async/await version
+"""
+# BEGIN FLAGS2_ASYNCIO_TOP
+import asyncio
+import collections
+
+import aiohttp
+from aiohttp import web
+import tqdm
+
+from flags2_common import main, HTTPStatus, Result, save_flag
+
+# default set low to avoid errors from remote site, such as
+# 503 - Service Temporarily Unavailable
+DEFAULT_CONCUR_REQ = 5
+MAX_CONCUR_REQ = 1000
+
+
+class FetchError(Exception):  # <1>
+
+    def __init__(self, country_code):
+        self.country_code = country_code
+
+
+async def get_flag(session, base_url, cc):  # <2>
+    url = '{}/{cc}/{cc}.gif'.format(base_url, cc=cc.lower())
+    async with session.get(url) as resp:
+        if resp.status == 200:
+            return await resp.read()
+        elif resp.status == 404:
+            raise web.HTTPNotFound()
+        else:
+            raise aiohttp.HttpProcessingError(code=resp.status, message=resp.reason, headers=resp.headers)
+
+
+async def download_one(session, cc, base_url, semaphore, verbose):  # <3>
+    try:
+        async with semaphore:  # <4>
+            image = await get_flag(session, base_url, cc)  # <5>
+    except web.HTTPNotFound:  # <6>
+        status = HTTPStatus.not_found
+        msg = 'not found'
+    except Exception as exc:
+        raise FetchError(cc) from exc  # <7>
+    else:
+        save_flag(image, cc.lower() + '.gif')  # <8>
+        status = HTTPStatus.ok
+        msg = 'OK'
+
+    if verbose and msg:
+        print(cc, msg)
+
+    return Result(status, cc)
+
+
+# END FLAGS2_ASYNCIO_TOP
+
+
+# BEGIN FLAGS2_ASYNCIO_DOWNLOAD_MANY
+async def downloader_coro(cc_list, base_url, verbose, concur_req):  # <1>
+    counter = collections.Counter()
+    semaphore = asyncio.Semaphore(concur_req)  # <2>
+    async with aiohttp.ClientSession() as session:  # <8>
+        to_do = [download_one(session, cc, base_url, semaphore, verbose) for cc in sorted(cc_list)]  # <3>
+
+        to_do_iter = asyncio.as_completed(to_do)  # <4>
+        if not verbose:
+            to_do_iter = tqdm.tqdm(to_do_iter, total=len(cc_list))  # <5>
+        for future in to_do_iter:  # <6>
+            try:
+                res = await future  # <7>
+            except FetchError as exc:  # <8>
+                country_code = exc.country_code  # <9>
+                try:
+                    error_msg = exc.__cause__.args[0]  # <10>
+                except IndexError:
+                    error_msg = exc.__cause__.__class__.__name__  # <11>
+                if verbose and error_msg:
+                    msg = '*** Error for {}: {}'
+                    print(msg.format(country_code, error_msg))
+                status = HTTPStatus.error
+            else:
+                status = res.status
+
+            counter[status] += 1  # <12>
+
+    return counter  # <13>
+
+
+def download_many(cc_list, base_url, verbose, concur_req):
+    loop = asyncio.get_event_loop()
+    coro = downloader_coro(cc_list, base_url, verbose, concur_req)
+    counts = loop.run_until_complete(coro)  # <14>
+    loop.close()  # <15>
+
+    return counts
+
+
+if __name__ == '__main__':
+    main(download_many, DEFAULT_CONCUR_REQ, MAX_CONCUR_REQ)
+# END FLAGS2_ASYNCIO_DOWNLOAD_MANY

pyPractice/fluent_python/chapter18-downloadflag2.py

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+"""Download flags of countries (with error handling).
+asyncio async/await version
+"""
+# BEGIN FLAGS2_ASYNCIO_TOP
+import asyncio
+import collections
+
+import aiohttp
+from aiohttp import web
+import tqdm
+
+from flags2_common import main, HTTPStatus, Result, save_flag
+
+# default set low to avoid errors from remote site, such as
+# 503 - Service Temporarily Unavailable
+DEFAULT_CONCUR_REQ = 5
+MAX_CONCUR_REQ = 1000
+
+
+class FetchError(Exception):  # <1>
+
+    def __init__(self, country_code):
+        self.country_code = country_code
+
+
+async def get_flag(session, base_url, cc):  # <2>
+    url = '{}/{cc}/{cc}.gif'.format(base_url, cc=cc.lower())
+    async with session.get(url) as resp:
+        if resp.status == 200:
+            return await resp.read()
+        elif resp.status == 404:
+            raise web.HTTPNotFound()
+        else:
+            raise aiohttp.HttpProcessingError(code=resp.status, message=resp.reason, headers=resp.headers)
+
+
+async def download_one(session, cc, base_url, semaphore, verbose):  # <3>
+    try:
+        async with semaphore:  # <4>
+            image = await get_flag(session, base_url, cc)  # <5>
+    except web.HTTPNotFound:  # <6>
+        status = HTTPStatus.not_found
+        msg = 'not found'
+    except Exception as exc:
+        raise FetchError(cc) from exc  # <7>
+    else:
+        save_flag(image, cc.lower() + '.gif')  # <8>
+        status = HTTPStatus.ok
+        msg = 'OK'
+
+    if verbose and msg:
+        print(cc, msg)
+
+    return Result(status, cc)
+
+
+# END FLAGS2_ASYNCIO_TOP
+
+
+# BEGIN FLAGS2_ASYNCIO_DOWNLOAD_MANY
+async def downloader_coro(cc_list, base_url, verbose, concur_req):  # <1>
+    counter = collections.Counter()
+    semaphore = asyncio.Semaphore(concur_req)  # <2>
+    async with aiohttp.ClientSession() as session:  # <8>
+        to_do = [download_one(session, cc, base_url, semaphore, verbose) for cc in sorted(cc_list)]  # <3>
+
+        to_do_iter = asyncio.as_completed(to_do)  # <4>
+        if not verbose:
+            to_do_iter = tqdm.tqdm(to_do_iter, total=len(cc_list))  # <5>
+        for future in to_do_iter:  # <6>
+            try:
+                res = await future  # <7>
+            except FetchError as exc:  # <8>
+                country_code = exc.country_code  # <9>
+                try:
+                    error_msg = exc.__cause__.args[0]  # <10>
+                except IndexError:
+                    error_msg = exc.__cause__.__class__.__name__  # <11>
+                if verbose and error_msg:
+                    msg = '*** Error for {}: {}'
+                    print(msg.format(country_code, error_msg))
+                status = HTTPStatus.error
+            else:
+                status = res.status
+
+            counter[status] += 1  # <12>
+
+    return counter  # <13>
+
+
+def download_many(cc_list, base_url, verbose, concur_req):
+    loop = asyncio.get_event_loop()
+    coro = downloader_coro(cc_list, base_url, verbose, concur_req)
+    counts = loop.run_until_complete(coro)  # <14>
+    loop.close()  # <15>
+
+    return counts
+
+
+if __name__ == '__main__':
+    main(download_many, DEFAULT_CONCUR_REQ, MAX_CONCUR_REQ)

pyPractice/practice/try_random.py

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+# coding:utf-8
+
+import random
+
+count1 = 0
+count2 = 0
+times = 10000
+
+for i in range(times):
+    aaa = random.choice(range(10))
+    print(aaa)
+    if aaa >= 3:
+        count1 += 1
+    else:
+        count2 += 1
+
+print(count1 / times)
+print(count2 / times)
+# random.