问题:如何在Flask中获取POST JSON?
我正在尝试使用Flask构建一个简单的API,现在我想在其中读取一些POSTed JSON。我使用Postman Chrome扩展程序执行POST,而我发布的JSON就是{"text":"lalala"}
。我尝试使用以下方法读取JSON:
@app.route('/api/add_message/<uuid>', methods=['GET', 'POST'])
def add_message(uuid):
content = request.json
print content
return uuid
在浏览器上,它可以正确返回我放入GET中的UUID,但是在控制台上,它只是打印出来None
(我希望它可以在其中打印出来{"text":"lalala"}
。有人知道我如何从Flask方法中获取发布的JSON吗?
I’m trying to build a simple API using Flask, in which I now want to read some POSTed JSON. I do the POST with the Postman Chrome extension, and the JSON I POST is simply {"text":"lalala"}
. I try to read the JSON using the following method:
@app.route('/api/add_message/<uuid>', methods=['GET', 'POST'])
def add_message(uuid):
content = request.json
print content
return uuid
On the browser it correctly returns the UUID I put in the GET, but on the console, it just prints out None
(where I expect it to print out the {"text":"lalala"}
. Does anybody know how I can get the posted JSON from within the Flask method?
回答 0
首先,该.json
属性是一个委托给request.get_json()
method的属性,该属性记录了为什么None
在此处看到。
您需要将请求内容类型设置为,application/json
以使.json
属性和.get_json()
方法(不带参数)起作用,None
否则两者都会产生这种情况。请参阅Flask Request
文档:
如果mimetype表示JSON(包含application / json,请参见),则它将包含已解析的JSON数据,否则为None
。
您可以request.get_json()
通过向其传递force=True
关键字参数来告知跳过内容类型要求。
请注意,如果此时引发异常(可能导致400 Bad Request响应),则您的JSON 数据无效。它在某种程度上畸形;您可能需要使用JSON验证程序进行检查。
First of all, the .json
attribute is a property that delegates to the request.get_json()
method, which documents why you see None
here.
You need to set the request content type to application/json
for the .json
property and .get_json()
method (with no arguments) to work as either will produce None
otherwise. See the Flask Request
documentation:
This will contain the parsed JSON data if the mimetype indicates JSON (application/json, see ), otherwise it will be None
.
You can tell request.get_json()
to skip the content type requirement by passing it the force=True
keyword argument.
Note that if an exception is raised at this point (possibly resulting in a 400 Bad Request response), your JSON data is invalid. It is in some way malformed; you may want to check it with a JSON validator.
回答 1
作为参考,以下是有关如何从Python客户端发送json的完整代码:
import requests
res = requests.post('http://localhost:5000/api/add_message/1234', json={"mytext":"lalala"})
if res.ok:
print res.json()
“ json =“输入将自动设置内容类型,如下所述:使用Python请求发布JSON
以上客户端将使用此服务器端代码:
from flask import Flask, request, jsonify
app = Flask(__name__)
@app.route('/api/add_message/<uuid>', methods=['GET', 'POST'])
def add_message(uuid):
content = request.json
print content['mytext']
return jsonify({"uuid":uuid})
if __name__ == '__main__':
app.run(host= '0.0.0.0',debug=True)
For reference, here’s complete code for how to send json from a Python client:
import requests
res = requests.post('http://localhost:5000/api/add_message/1234', json={"mytext":"lalala"})
if res.ok:
print res.json()
The “json=” input will automatically set the content-type, as discussed here: Post JSON using Python Requests
And the above client will work with this server-side code:
from flask import Flask, request, jsonify
app = Flask(__name__)
@app.route('/api/add_message/<uuid>', methods=['GET', 'POST'])
def add_message(uuid):
content = request.json
print content['mytext']
return jsonify({"uuid":uuid})
if __name__ == '__main__':
app.run(host= '0.0.0.0',debug=True)
回答 2
这就是我要做的方法,应该是
@app.route('/api/add_message/<uuid>', methods=['GET', 'POST'])
def add_message(uuid):
content = request.get_json(silent=True)
# print(content) # Do your processing
return uuid
随着silent=True
集,该get_json
功能将尝试检索JSON的身体的时候默默的失败。默认情况下,此设置为False
。如果您始终希望使用json正文(而不是可选),请将其保留为silent=False
。
设置force=True
将忽略request.headers.get('Content-Type') == 'application/json'
烧瓶对您的
检查。默认情况下,它也设置为False
。
请参见烧瓶文档。
我强烈建议您离开force=False
并让客户端发送Content-Type
标头以使其更加明确。
希望这可以帮助!
This is the way I would do it and it should be
@app.route('/api/add_message/<uuid>', methods=['GET', 'POST'])
def add_message(uuid):
content = request.get_json(silent=True)
# print(content) # Do your processing
return uuid
With silent=True
set, the get_json
function will fail silently when trying to retrieve the json body. By default this is set to False
. If you are always expecting a json body (not optionally), leave it as silent=False
.
Setting force=True
will ignore the
request.headers.get('Content-Type') == 'application/json'
check that flask does for you. By default this is also set to False
.
See flask documentation.
I would strongly recommend leaving force=False
and make the client send the Content-Type
header to make it more explicit.
Hope this helps!
回答 3
假设您已发布具有application/json
内容类型的有效JSON ,request.json
将具有已解析的JSON数据。
from flask import Flask, request, jsonify
app = Flask(__name__)
@app.route('/echo', methods=['POST'])
def hello():
return jsonify(request.json)
Assuming you’ve posted valid JSON with the application/json
content type, request.json
will have the parsed JSON data.
from flask import Flask, request, jsonify
app = Flask(__name__)
@app.route('/echo', methods=['POST'])
def hello():
return jsonify(request.json)
回答 4
对于所有问题都是来自ajax调用的人,这里有一个完整的示例:
Ajax调用:这里的关键是使用a dict
然后JSON.stringify
var dict = {username : "username" , password:"password"};
$.ajax({
type: "POST",
url: "http://127.0.0.1:5000/", //localhost Flask
data : JSON.stringify(dict),
contentType: "application/json",
});
在服务器端:
from flask import Flask
from flask import request
import json
app = Flask(__name__)
@app.route("/", methods = ['POST'])
def hello():
print(request.get_json())
return json.dumps({'success':True}), 200, {'ContentType':'application/json'}
if __name__ == "__main__":
app.run()
For all those whose issue was from the ajax call, here is a full example :
Ajax call : the key here is to use a dict
and then JSON.stringify
var dict = {username : "username" , password:"password"};
$.ajax({
type: "POST",
url: "http://127.0.0.1:5000/", //localhost Flask
data : JSON.stringify(dict),
contentType: "application/json",
});
And on server side :
from flask import Flask
from flask import request
import json
app = Flask(__name__)
@app.route("/", methods = ['POST'])
def hello():
print(request.get_json())
return json.dumps({'success':True}), 200, {'ContentType':'application/json'}
if __name__ == "__main__":
app.run()
回答 5
给出另一种方法。
from flask import Flask, jsonify, request
app = Flask(__name__)
@app.route('/service', methods=['POST'])
def service():
data = json.loads(request.data)
text = data.get("text",None)
if text is None:
return jsonify({"message":"text not found"})
else:
return jsonify(data)
if __name__ == '__main__':
app.run(host= '0.0.0.0',debug=True)
To give another approach.
from flask import Flask, jsonify, request
app = Flask(__name__)
@app.route('/service', methods=['POST'])
def service():
data = json.loads(request.data)
text = data.get("text",None)
if text is None:
return jsonify({"message":"text not found"})
else:
return jsonify(data)
if __name__ == '__main__':
app.run(host= '0.0.0.0',debug=True)
回答 6
假设您发布了有效的JSON,
@app.route('/api/add_message/<uuid>', methods=['GET', 'POST'])
def add_message(uuid):
content = request.json
print content['uuid']
# Return data as JSON
return jsonify(content)
Assuming that you have posted valid JSON,
@app.route('/api/add_message/<uuid>', methods=['GET', 'POST'])
def add_message(uuid):
content = request.json
print content['uuid']
# Return data as JSON
return jsonify(content)
回答 7
尝试使用力参数…
request.get_json(force = True)
Try to use force parameter…
request.get_json(force = True)
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