我正在使用Azure通知中心将Raspberry pi的推送通知发送到Android应用程序。
我根据这篇文章How to use Notification Hubs from Python
使用REST API使用python客户端应用程序一切正常但从Raspberry pi到Android应用程序的每个通知中都有近2秒的延迟！如何避免此延迟并在同一秒内在Android设备上获取通知。
我的python脚本
import time
import hmac
import base64
import hashlib
import json
import urllib.parse
import http.client
class Notification:
def __init__(self, notification_format=None, payload=None, debug=0):
valid_formats = ['template', 'apple', 'gcm', 'windows', 'windowsphone', "adm", "baidu"]
if not any(x in notification_format for x in valid_formats):
raise Exception(
"Invalid Notification format. " +
"Must be one of the following - 'template', 'apple', 'gcm', 'windows', 'windowsphone', 'adm', 'baidu'")
self.format = notification_format
self.payload = payload
# array with keynames for headers
# Note: Some headers are mandatory: Windows: X-WNS-Type, WindowsPhone: X-NotificationType
# Note: For Apple you can set Expiry with header: ServiceBusNotification-ApnsExpiry
# in W3C DTF, YYYY-MM-DDThh:mmTZD (for example, 1997-07-16T19:20+01:00).
self.headers = None
class NotificationHub:
API_VERSION = "?api-version=2013-10"
DEBUG_SEND = "&test"
def __init__(self, connection_string=None, hub_name=None, debug=0):
self.HubName = hub_name
self.Debug = debug
# Parse connection string
parts = connection_string.split(';')
if len(parts) != 3:
raise Exception("Invalid ConnectionString.")
for part in parts:
if part.startswith('Endpoint'):
self.Endpoint = 'https' + part[11:]
if part.startswith('SharedAccessKeyName'):
self.SasKeyName = part[20:]
if part.startswith('SharedAccessKey'):
self.SasKeyValue = part[16:]
@staticmethod
def get_expiry():
# By default returns an expiration of 5 minutes (=300 seconds) from now
return int(round(time.time() + 300))
@staticmethod
def encode_base64(data):
return base64.b64encode(data)
def sign_string(self, to_sign):
key = self.SasKeyValue.encode('utf-8')
to_sign = to_sign.encode('utf-8')
signed_hmac_sha256 = hmac.HMAC(key, to_sign, hashlib.sha256)
digest = signed_hmac_sha256.digest()
encoded_digest = self.encode_base64(digest)
return encoded_digest
def generate_sas_token(self):
target_uri = self.Endpoint + self.HubName
my_uri = urllib.parse.quote(target_uri, '').lower()
expiry = str(self.get_expiry())
to_sign = my_uri + '\n' + expiry
signature = urllib.parse.quote(self.sign_string(to_sign))
auth_format = 'SharedAccessSignature sig={0}&se={1}&skn={2}&sr={3}'
sas_token = auth_format.format(signature, expiry, self.SasKeyName, my_uri)
return sas_token
def make_http_request(self, url, payload, headers):
parsed_url = urllib.parse.urlparse(url)
connection = http.client.HTTPSConnection(parsed_url.hostname, parsed_url.port)
if self.Debug > 0:
connection.set_debuglevel(self.Debug)
# adding this querystring parameter gets detailed information about the PNS send notification outcome
url += self.DEBUG_SEND
print("--- REQUEST ---")
print("URI: " + url)
print("Headers: " + json.dumps(headers, sort_keys=True, indent=4, separators=(' ', ': ')))
print("--- END REQUEST ---\n")
connection.request('POST', url, payload, headers)
response = connection.getresponse()
if self.Debug > 0:
# print out detailed response information for debugging purpose
print("\n\n--- RESPONSE ---")
print(str(response.status) + " " + response.reason)
print(response.msg)
print(response.read())
print("--- END RESPONSE ---")
elif response.status != 201:
# Successful outcome of send message is HTTP 201 - Created
raise Exception(
"Error sending notification. Received HTTP code " + str(response.status) + " " + response.reason)
connection.close()
def send_notification(self, notification, tag_or_tag_expression=None):
url = self.Endpoint + self.HubName + '/messages' + self.API_VERSION
json_platforms = ['template', 'apple', 'gcm', 'adm', 'baidu']
if any(x in notification.format for x in json_platforms):
content_type = "application/json"
payload_to_send = json.dumps(notification.payload)
else:
content_type = "application/xml"
payload_to_send = notification.payload
headers = {
'Content-type': content_type,
'Authorization': self.generate_sas_token(),
'ServiceBusNotification-Format': notification.format
}
if isinstance(tag_or_tag_expression, set):
tag_list = ' || '.join(tag_or_tag_expression)
else:
tag_list = tag_or_tag_expression
# add the tags/tag expressions to the headers collection
if tag_list != "":
headers.update({'ServiceBusNotification-Tags': tag_list})
# add any custom headers to the headers collection that the user may have added
if notification.headers is not None:
headers.update(notification.headers)
self.make_http_request(url, payload_to_send, headers)
def send_apple_notification(self, payload, tags=""):
nh = Notification("apple", payload)
self.send_notification(nh, tags)
def send_gcm_notification(self, payload, tags=""):
nh = Notification("gcm", payload)
self.send_notification(nh, tags)
def send_adm_notification(self, payload, tags=""):
nh = Notification("adm", payload)
self.send_notification(nh, tags)
def send_baidu_notification(self, payload, tags=""):
nh = Notification("baidu", payload)
self.send_notification(nh, tags)
def send_mpns_notification(self, payload, tags=""):
nh = Notification("windowsphone", payload)
if "<wp:Toast>" in payload:
nh.headers = {'X-WindowsPhone-Target': 'toast', 'X-NotificationClass': '2'}
elif "<wp:Tile>" in payload:
nh.headers = {'X-WindowsPhone-Target': 'tile', 'X-NotificationClass': '1'}
self.send_notification(nh, tags)
def send_windows_notification(self, payload, tags=""):
nh = Notification("windows", payload)
if "<toast>" in payload:
nh.headers = {'X-WNS-Type': 'wns/toast'}
elif "<tile>" in payload:
nh.headers = {'X-WNS-Type': 'wns/tile'}
elif "<badge>" in payload:
nh.headers = {'X-WNS-Type': 'wns/badge'}
self.send_notification(nh, tags)
def send_template_notification(self, properties, tags=""):
nh = Notification("template", properties)
self.send_notification(nh, tags)
isDebug = True
myConnectionString = "connection string"
hub = NotificationHub(myConnectionString, "cavenotificationhub", isDebug)
data = {}
data['response'] = 'data: R1|X1|S1,1|$'
json_data = json.dumps(data,separators=(',',':'))
print(json_data)
#gcm_payload = {"response":R1|X1|S1,1}
val= "R1|X1|S1,1|$"
gcm_payload = { 'data' : {'response': ''+val+''}}
hub.send_gcm_notification(gcm_payload)
附加日志：
Windows 10 Surface Pro 3 - Python 3.4 script
**** Send GCM Notitification START> 2016-05-08 10:42:07.883226
*** make_http_request connection OPEN> 2016-05-08 10:42:08.139328
--- REQUEST ---
#Request header
--- END REQUEST ---
*** make_http_request START> 2016-05-08 10:42:08.165356
#Sending request to Azure
*** make_http_request END> 2016-05-08 10:42:09.016024
--- RESPONSE ---
#Response received from Azure
--- END RESPONSE ---
*** make_http_request connection CLOSE> 2016-05-08 10:42:09.184785
**** Send GCM Notitification END> 2016-05-08 10:42:09.188788
################################################################################################################################ Raspberry Pi Model B+ V1.2 - Python 2.7 script
('*** Send GCM Notitification START> ', '2016-05-08 10:46:32.692844') ('*** make_http_request connection OPEN> ', '2016-05-08 10:46:32.698456')
--- REQUEST ---
#Request header
--- END REQUEST ---
('*** make_http_request START> ', '2016-05-08 10:46:32.705946')
#Sending request to Azure ('*** make_http_request END> ', '2016-05-08 10:46:39.557759')
--- RESPONSE ---
#Response received from Azure
--- END RESPONSE ---
('*** make_http_request connection CLOSE> ', '2016-05-08 10:46:39.569713') ('*** Send GCM Notitification END> ', '2016-05-08 10:46:39.570986')
################################################################################################################################ Raspberry Pi 2 Model B V1.1 - Python 2.7 script
('*** Send GCM Notitification START> ', '2016-05-08 05:36:49.721024') ('*** make_http_request connection OPEN> ', '2016-05-08 05:36:49.732056')
--- REQUEST ---
#Request header
--- END REQUEST ---
('*** make_http_request START> ', '2016-05-08 05:36:49.733069')
#Sending request to Azure ('*** make_http_request END> ', '2016-05-08 05:36:50.741605')
--- RESPONSE ---
#Response received from Azure
--- END RESPONSE ---
('*** make_http_request connection CLOSE> ', '2016-05-08 05:36:50.746248') ('*** Send GCM Notitification END> ', '2016-05-08 05:36:50.747000')
答案 0 :(得分：2)
这很难！首先，我们需要了解这个问题的原因。
1）从Raspberry Pi 2到后端的请求可能很长。要了解这是否是问题，请使用Service Bus Explorer，连接到SB命名空间，然后打开Notification Hub，选择Android窗格并尝试从该窗格发送推送（请参见屏幕截图）。如果您能更快地收到通知，那么RPI就会以某种方式参与其中。
2）如果您发现延迟没有差异，并且使用RPI或SB发送通知导致2-3秒后推送，那么我会说它绝对没问题。例如See that topic。这实际上取决于很多因素，当我们试图减少时间时（我们有时会观察5-10秒），我们发现经常出现的问题不是客户端或经纪人（在这种情况下是NH），而是通知平台。
当然，你不应该期望在同一时间发送通知。我们有最好的 - 接下来或2秒后。但实际上并没有保证。