查询在网络浏览器中工作，但在 R 中得到 400 Bad Request？

Question

我在 R 中遇到了查询 Facebook Graph API 的问题。在以下代码中，我删除了版本、行为和 access_token。如果我将此查询粘贴到 Web 浏览器中，它可以正常工作。

https://graph.facebook.com/vX.X/act_XXXXXXXXXXXXXXXXX/delivery_estimate?access_token= &include_headers=false&method=get&optimization_goal=REACH&pretty=0&suppress_http_code=1&targeting_spec={"age_min":13,"age_max":24,"genders":[1],"flexible_spec":[{"behaviors":[{"id":"6025000826583","name":"Vivieron en Argentina (anteriormente expatriados - Argentina)"}]}],"geo_locations":{"countries":["BR"],"location_types":["home"]},"facebook_positions":["feed","instant_article","instream_video","marketplace"],"device_platforms":["mobile","desktop"],"publisher_platforms":["facebook","messenger"],"messenger_positions":["messenger_home"]}

R 中使用url() 函数的等效查询是：

"https://graph.facebook.com/vX.X/act_XXXXXXXXXXXXXXXXX/delivery_estimate?access_token= &include_headers=false&method=get&optimization_goal=REACH&pretty=0&suppress_http_code=1&targeting_spec={\"age_min\":13,\"age_max\":24,\"genders\":[1],\"flexible_spec\":[{\"behaviors\":[{\"id\":\"6025000826583\",\"name\":\"Vivieron en Argentina (anteriormente expatriados - Argentina)\"}]}],\"geo_locations\":{\"countries\":[\"BR\"],\"location_types\":[\"home\"]},\"facebook_positions\":[\"feed\",\"instant_article\",\"instream_video\",\"marketplace\"],\"device_platforms\":[\"mobile\",\"desktop\"],\"publisher_platforms\":[\"facebook\",\"messenger\"],\"messenger_positions\":[\"messenger_home\"]}"

但是当我的程序在 Linux 中执行时，响应是：

    *   Trying 31.13.83.8...
    * TCP_NODELAY set
    * Connected to graph.facebook.com (31.13.83.8) port 443 (#0)
    * ALPN, offering http/1.1
    * successfully set certificate verify locations:
    *   CAfile: /etc/ssl/certs/ca-certificates.crt
      CApath: /etc/ssl/certs
    * SSL connection using TLSv1.3 / TLS_CHACHA20_POLY1305_SHA256
    * ALPN, server accepted to use http/1.1
    * Server certificate:
    *  subject: C=US; ST=California; L=Menlo Park; O=Facebook, Inc.; CN=*.facebook.com
    *  start date: Nov  6 00:00:00 2019 GMT
    *  expire date: Feb  4 12:00:00 2020 GMT
    *  subjectAltName: host "graph.facebook.com" matched cert's "*.facebook.com"
    *  issuer: C=US; O=DigiCert Inc; OU=www.digicert.com; CN=DigiCert SHA2 High Assurance Server CA
    *  SSL certificate verify ok.
    > GET ...

     HTTP/1.1
    Host: graph.facebook.com
    User-Agent: R (3.4.4 x86_64-pc-linux-gnu x86_64 linux-gnu)
    Accept: */*

    * The requested URL returned error: 400 Bad Request
    * stopped the pause stream!
    * Closing connection 0

我对这个问题很困惑。

最好的问候， 马丁

Answer 1

您应该使用JSON 有效负载，而不是像浏览器那样在 url 中编码请求

TL;DR

试试这样的：

install.packages("httr");
install.packages("jsonlite")
library(jsonlite)
library("httr");
url = "https://graph.facebook.com/vX.X/act_XXXXXXXXXXXXXXXXX/delivery_estimate";
targeting_spec <- fromJSON({"age_min":13,"age_max":24,"genders":[1],"flexible_spec":[{"behaviors":[{"id":"6025000826583","name":"Vivieron en Argentina (anteriormente expatriados - Argentina)"}]}],"geo_locations":{"countries":["BR"],"location_types":["home"]},"facebook_positions":["feed","instant_article","instream_video","marketplace"],"device_platforms":["mobile","desktop"],"publisher_platforms":["facebook","messenger"],"messenger_positions":["messenger_home"]});
POST(url,body=targeting_spec,encode='json');

说明

让我们从浏览器中的工作查询开始

你是对的，网址在浏览器中有效。 由于缺少auth_token，出现错误响应"Unknown path components: /act_XXXXXXXXXXXXXXXXX/delivery_estimate"，但这不是问题。

让我们检查一下curl

如果您尝试使用 curl 的相同 url，您将收到错误消息：

curl: (3) [globbing] nested brace in column 229

啊哈时刻：你应该对你的有效载荷进行编码

您的问题中有JSON：

targeting_spec={"age_min":13,"age_max":24,"genders":[1],"flexible_spec":[{"behaviors":[{"id":"6025000826583","name":"Vivieron en Argentina (anteriormente expatriados - Argentina)"}]}],"geo_locations":{"countries":["BR"],"location_types":["home"]},"facebook_positions":["feed","instant_article","instream_video","marketplace"],"device_platforms":["mobile","desktop"],"publisher_platforms":["facebook","messenger"],"messenger_positions":["messenger_home"]}

好吧，让我们尝试使用curl -d 参数从您的网址中删除JSON 部分：

curl -i 'https://graph.facebook.com/vX.X/act_XXXXXXXXXXXXXXXXX/delivery_estimate?include_headers=false&method=get&optimization_goal=REACH&pretty=0&suppress_http_code=1' \
-d 'targeting_spec={%22age_min%22:13,%22age_max%22:24,%22genders%22:[1],%22flexible_spec%22:[{%22behaviors%22:[{%22id%22:%226025000826583%22,%22name%22:%22Vivieron%20en%20Argentina%20(anteriormente%20expatriados%20-%20Argentina)%22}]}],%22geo_locations%22:{%22countries%22:[%22BR%22],%22location_types%22:[%22home%22]},%22facebook_positions%22:[%22feed%22,%22instant_article%22,%22instream_video%22,%22marketplace%22],%22device_platforms%22:[%22mobile%22,%22desktop%22],%22publisher_platforms%22:[%22facebook%22,%22messenger%22],%22messenger_positions%22:[%22messenger_home%22]}'

-i 将在输出中包含 HTTP 响应标头，-d 告诉curl 有JSON 有效负载。

curl 的输出是：

HTTP/2 200
x-app-usage: {"call_count":0,"total_cputime":0,"total_time":0}
www-authenticate: OAuth "Facebook Platform" "invalid_request" "Unknown path components: /act_XXXXXXXXXXXXXXXXX/delivery_estimate"
content-type: application/json; charset=UTF-8
facebook-api-version: v2.11
strict-transport-security: max-age=15552000; preload
pragma: no-cache
x-fb-rev: 1001479573
access-control-allow-origin: *
cache-control: no-store
x-fb-trace-id: E736hUurL6h
x-fb-request-id: A6vLWQz7xHTyoFSFKSNrBQb
expires: Sat, 01 Jan 2000 00:00:00 GMT
x-fb-debug: t1UMuN4vVdGU7O1h9NM5xujWahT/6YMANIhxYBqKjkLWQ2D+dDpuIT8QhI2UtzPj9Gp3RpJb7kM9RoaIGgMlxw==
content-length: 166
date: Thu, 28 Nov 2019 21:53:12 GMT
alt-svc: h3-23=":443"; ma=3600

{"error":{"message":"Unknown path components: \/act_XXXXXXXXXXXXXXXXX\/delivery_estimate","type":"OAuthException","code":2500,"fbtrace_id":"A6vLWQz7xHTyoFSFKSNrBQb"}}%

这与您从浏览器获得的结果相同，而无需传递您从问题中删除的身份验证令牌。

最终结果

要告诉 R url() 函数你有 JSON 有效载荷，只需使用 POST(url, body=b,encode='json');

最后，你得到了应该工作的代码。