async def download_one(cc):
#image = yield from get_flag(cc)
async with aiohttp.ClientSession() as session:
image = await (get_flag(session, cc))
show(cc)
save_flag(image, cc.lower() + '.png')
return cc
def download_one(cc, base_url, verbose=False):
try:
image = get_flag(base_url, cc)
# download_oneはrequests.exceptions.HTTPErrorをキャッチし、
# HTTPステータスコード404を処理します。
except requests.exeptions.HTTPError as exc:
res = exc.response
if res.status_code == 404:
# ステータスコードが404なら、
# ここ独自のステータス（status）にHTTPStatus.not_foundを割り当てます。
# なお、HTTPStatusはEnumで、flags2_commonからインポートされます。
status = HTTPStatus.not_found
msg = 'not found'
else:
# 例外HTTPErrorが404以外なら再度上げられ、
# 呼び出し元へと伝播されます。
raise
else:
save_flag(iamge, cc.lower() + '.gif')
status = HTTPStatus.ok
msg = 'OK'
# コマンドラインの-v/--verboseはverbose（詳細表示）オプションで、デフォルトではオフです。
# これが指定されたら、進行状況を確認できるように国別コードとステータスメッセージを表示します。
if verbose:
print(cc, msg)
# downlaod_oneはnamedtupleのResultを返します。Resultにはstatusフィールドがあり、
# HTTPStatus.not_foundかHTTPStatus.okのどちらかの値が収容されています。
return Result(status, cc)
def download_one(cc, base_url, semaphore, verbose):
try:
with (yield from semaphore):
image = yield from get_flag(base_url, cc)
except web.HTTPNotFound:
status = HTTPStatus.not_found
msg = 'not found'
except Exception as exc:
raise FetchError(cc) from exc
else:
save_flag(image, cc.lower() + '.gif')
status = HTTPStatus.ok
msg = 'OK'
if verbose and msg:
print(cc, msg)
return Result(status, cc)
def download_one(cc, base_url, semaphore, verbose): # ➌ semaphore 参数是 asyncio.Semaphore 类的实例。Semaphore 类是同步装置，用于限制并发请求数量。
try:
with (yield from semaphore): # ➍ 在yield from 表达式中把 semaphore 当成上下文管理器使用，防止阻塞整个系统：如果semaphore 计数器的值是所允许的最大值，只有这个协程会阻塞。
image = yield from get_flag(base_url, cc) # ➎ 退出这个with 语句后，semaphore 计数器的值会递减，解除阻塞可能在等待同一个 semaphore 对象的其他协程实例。
except web.HTTPNotFound: # ➏ 如果没找到国旗，相应地设置Result 的状态。
status = HTTPStatus.not_found
msg = 'not found'
except Exception as exc:
raise FetchError(cc) from exc # ➐ 其他异常当作FetchError 抛出， 传入国家代码， 并使用“PEP 3134 — Exception Chaining and Embedded Tracebacks”（https://www.python.org/dev/peps/pep-3134/）引入的raise X from Y 句法链接原来的异常。
else:
save_flag(image, cc.lower() + '.gif') # ➑ 这个函数的作用是把国旗文件保存到硬盘中。
status = HTTPStatus.ok
msg = 'OK'
if verbose and msg:
print(cc, msg)
return Result(status, cc)
def download_one(cc, base_url, verbose=False):
try:
image = get_flag(base_url, cc)
except requests.exceptions.HTTPError as exc:
res = exc.response
if res.status_code == 404:
status = HTTPStatus.not_found
msg = 'not found'
else:
raise
else:
save_flag(image, cc.lower() + '.gif')
status = HTTPStatus.ok
msg = 'OK'
if verbose:
print(cc, msg)
return Result(status, cc)
async def download_one(cc, base_url, semaphore, verbose): # <3>
try:
with (await semaphore): # <4>
image = await get_flag(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)
def download_one(cc, base_url, verbose=False):
try:
image = get_flag(base_url, cc)
except requests.exceptions.HTTPError as exc:
res = exc.response
if res.status_code == 404: #如果异常是404，则会被压下来，而不传到download_many函数
status = HTTPStatus.not_found #是个枚举成员
msg = 'not found'
else:
raise
else:
save_flag(image, cc.lower() + '.gif')
status = HTTPStatus.ok #是个枚举成员
msg = 'ok'
if verbose:
print(cc, msg)
return Result(status, cc) #具名元组的第一字段是个枚举成员，第二字段是个国旗代码字符串
def download_one(cc, base_url, semaphore, verbose): #3
try:
with (yield from semaphore): #4
image = yield from get_flag(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)
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)
def download_one(cc: str, base_url: str, verbose: bool = False):
try:
image = get_flag(base_url, cc)
except requests.exceptions.HTTPError as exc: # <2>
res = exc.response
if res.status_code == 404:
status = HTTPStatus.not_found # <3>
msg = 'not found'
else: # <4>
raise
else:
save_flag(image, f'{cc}.gif')
status = HTTPStatus.ok
msg = 'OK'
if verbose: # <5>
print(cc, msg)
return Result(status, cc) # <6>
def download_one(cc, base_url, verbose=False):
try:
image = get_flag(base_url, cc)
except requests.exceptions.HTTPError as exc: # 捕获 requests.exceptions.HTTPError 异常
res = exc.response
if res.status_code == 404: # 特别处理 HTTP 404 错误
status = HTTPStatus.not_found # HTTPStatus 为 Enum 对象
msg = 'not found'
else: # 重新抛出其他 HTTPError 异常，这些异常会向上冒泡，传给调用方
raise
else:
save_flag(image, cc.lower() + '.gif')
status = HTTPStatus.ok
msg = 'OK'
if verbose: # 通过 -v/--verbose 选项来选择是否显示国家代码和状态信息
print(cc, msg)
return Result(status, cc)
def download_one(cc, base_url, verbose=False):
try:
image = get_flag(base_url, cc)
except requests.exceptions.HTTPError as exc: # <2>
res = exc.response
if res.status_code == 404:
status = HTTPStatus.not_found # <3>
msg = 'not found'
else: # <4>
raise
else:
save_flag(image, cc.lower() + '.gif')
status = HTTPStatus.ok
msg = 'OK'
if verbose: # <5>
print(cc, msg)
return Result(status, cc) # <6>
def download_one(cc, base_url, verbose=False):
try:
image = get_flag(base_url, cc)
except httpx._exceptions.HTTPError as exc: # <2>
resp = exc.response
if resp is not None and resp.status_code == 404:
status = HTTPStatus.not_found # <3>
msg = 'not found'
else: # <4>
raise
else:
save_flag(image, cc.lower() + '.gif')
status = HTTPStatus.ok
msg = 'OK'
if verbose: # <5>
print(cc, msg)
return Result(status, cc) # <6>
def download_one(cc, base_url, verbose=False): # 负责下载的基本函数
try:
image = get_flag(base_url, cc)
except requests.exceptions.HTTPError as exc: # 捕获异常，这里专门处理HTTP 404错误，其他异常不管
res = exc.response
if res.status_code == 404: # 处理HTTP 404错误
status = HTTPStatus.not_found
msg = 'not found'
else: # 重新抛出其他异常，向上冒泡传给调用方
raise
else:
save_flag(image, cc.lower() + '.gif')
status = HTTPStatus.ok
msg = 'OK'
if verbose: # 如果在命令行中设定了 -v/--verbose 选项，显示国家代码和状态消息（即详细模式）
print(cc, msg)
return Result(status, cc) # 返回一个命名元组，其中有个status字段，其值是HTTPStatus.not_found或HTTPStatus.ok
def download_one(cc, base_url, verbose=False):
try:
image = get_flag(base_url, cc)
country = get_country(base_url, cc)
except requests.exceptions.HTTPError as exc:
res = exc.response
if res.status_code == 404:
status = HTTPStatus.not_found
msg = 'not found'
else: # <4>
raise
else:
country = country.replace(' ', '_')
save_flag(image, '{}-{}.gif'.format(country, cc))
status = HTTPStatus.ok
msg = 'OK'
if verbose:
print(cc, msg)
return Result(status, cc)
def download_one(cc, base_url, verbose=False):
try:
image = get_flag(base_url, cc)
country = get_country(base_url, cc)
except requests.exceptions.HTTPError as exc:
res = exc.response
if res.status_code == 404:
status = HTTPStatus.not_found
msg = 'not found'
else: # <4>
raise
else:
country = country.replace(' ', '_')
save_flag(image, '{}-{}.gif'.format(country, cc))
status = HTTPStatus.ok
msg = 'OK'
if verbose:
print(cc, msg)
return Result(status, cc)
async def download_one(
session: aiohttp.ClientSession, # <4>
cc: str,
base_url: str,
semaphore: asyncio.Semaphore,
verbose: bool) -> Result:
try:
async with semaphore: # <5>
image = await get_flag(session, base_url, cc)
except aiohttp.ClientResponseError as exc:
if exc.status == 404: # <6>
status = HTTPStatus.not_found
msg = 'not found'
else:
raise FetchError(cc) from exc # <7>
else:
save_flag(image, f'{cc}.gif')
status = HTTPStatus.ok
msg = 'OK'
if verbose and msg:
print(cc, msg)
return Result(status, cc)
def download_one(
cc, base_url, semaphore, verbose
): # semaphore参数是asyncio.Semaphore类的实例，Semaphore类是同步装置，用于限制并发请求数量
try:
with (
yield from semaphore
): # 在yield from表达式中把semaphore当成上下文管理器使用，防止阻塞整个系统：如果semaphore计数器的值是所允许的最大值，只有这个协程会阻塞
image = yield from get_flag(
base_url, cc
) # 退出这个with语句后，semaphore计数器的值会递减，解除阻塞可能在等待同一个semaphore对象的其他协程实例
except web.HTTPNotFound: # 如果没有找到国旗，设置Result的状态
status = HTTPStatus.not_found
msg = 'not found'
except Exception as exc: # 其他异常当作FetchError抛出，传入国家代码
raise FetchError(cc) from exc
else:
save_flag(image, cc.lower() + '.gif')
status = HTTPStatus.ok
msg = 'OK'
if verbose and msg:
print(cc, msg)
return Result(status, cc)
def download_one(cc, base_url, semaphor, verbose):
try:
# A semaphore is used as a context manager in a yield from expression so that the system as a whole is NOT blocked: only this coroutine is blocked while the semaphore counter is at the maximum allowed number
# guarantees that NO MORE than concur_req instances of get_flags coroutines will be started at any time
with (yield from semaphore):
# When this with statement exits, the semaphore counter is decreased, unblocking some other coroutine instance that may be waiting for the same semaphore object
image = yield from get_flag(base_url, cc)
# if the flag was NOT found, just set the status for the Result accordingly
except web.HTTPNotFound:
status = HTTPStatus.not_found
msg = 'not found'
except Exception as exc:
# Any other exception will be reported as a FetchError with the country code and the original exception chained using the raise X from Y syntax
# Explicit Exception Chaining
raise FetchError(cc) from exc
else:
# this function call actually saves the flag image to disk
save_flag(image, cc.lower() + '.gif')
status = HTTPStatus.ok
msg = 'OK'
if verbose and msg:
print(cc, msg)
return Result(status, cc)
def download_one(cc, base_url, verbose=False):
try:
image = get_flag(base_url, cc)
# download_one catches requests.exceptions.HTTPError to handle HTTP code 404 specifically
except requests.exceptions.HTTPError as exc:
res = exc.response
if res.status_code == 404:
# by setting its local status to HTTPStatus.not_found; HTTPStatus is an Enum imported from flags2_common
status = HTTPStatus.not_found
msg = 'not found'
# Any other HTTPError exception is re-raised; other exceptions will just propagate to the caller
else:
raise
else:
save_flag(image, cc.lower() + '.gif')
status = HTTPStatus.ok
msg = 'OK'
# If the -v/--verbose command-line option is set, the country code and status message will be displayed; this is how you'll see progress in the verbose mode
if verbose:
print(cc, msg)
# The Result namedtuple returned by download_one, will have a status field with a value of HTTPStatus.not_found or HTTPStatus.ok
return Result(status, cc)
