如何让 httr POST 请求在 R 中工作？

Question

我正在尝试连接到 Oanda API 但很难正确格式化我的请求。

API 文档需要以下格式：

body=$(cat << EOF
{
  "order": {
    "price": "1.2000",
    "timeInForce": "GTC",
    "instrument": "EUR_CAD",
    "units": "10000",
    "clientExtensions": {
      "comment": "New idea for trading",
      "tag": "strategy_9",
      "id": "my_order_100"
    },
    "type": "MARKET_IF_TOUCHED",
    "positionFill": "DEFAULT"
  }
}
EOF
)

curl \
  -X POST \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <AUTHENTICATION TOKEN>" \
  -d "$body" \
  "https://api-fxtrade.oanda.com/v3/accounts/<ACCOUNT>/orders"

我的要求如下：

    require(httr)
    body = list(instrument="EUR_USD", #These 4 are the required fields for this order type
         units="1", 
         side="buy", 
         type="market"
)

auth = paste("Authorization: Bearer ",Token)

POST(add_headers("Content-Type: application/json",auth),
     body = body,
     url = 'https://api-fxpractice.oanda.com')

但是，我收到以下响应 404：

    Response [https://api-fxpractice.oanda.com]
      Date: 2020-03-27 09:53
      Status: 404
      Content-Type: application/json
      Size: 170 B
    {
        "code" : 38,
        "message" : "No matching handler for the request is found",
        "moreInfo" : "http:\/\/developer.oanda.com\/docs\/v1\/troubleshooting\/#errors"
    }

我做错了什么？

Answer 1

您缺少订单，需要将您的请求明确转换为 json。试一试：

library("RCurl")
library("rjson")

# Accept SSL certificates issued by public Certificate Authorities
options(RCurlOptions = list(cainfo = system.file("CurlSSL", "cacert.pem", package = "RCurl")))

h = basicTextGatherer()
hdr = basicHeaderGatherer()


req = list(
        order = list(instrument="EUR_USD",
                        units="1", 
                        side="buy", 
                        type="market")
)

body = enc2utf8(toJSON(req))
Token = "abc123" # Replace this with the API key for the web service
authz_hdr = paste('Bearer', Token, sep=' ')

h$reset()
curlPerform(url = "",
            httpheader=c('Content-Type' = "application/json", 'Authorization' = authz_hdr),
            postfields=body,
            writefunction = h$update,
            headerfunction = hdr$update,
            verbose = TRUE
            )

headers = hdr$value()
httpStatus = headers["status"]
if (httpStatus >= 400)
{
    print(paste("The request failed with status code:", httpStatus, sep=" "))

    # Print the headers - they include the requert ID and the timestamp, which are useful for debugging the failure
    print(headers)
}

print("Result:")
result = h$value()
print(fromJSON(result))

我的猜测是它被自动转换成文本，并且没有匹配文本的处理程序方法

如何让 httr POST 请求在 R 中工作？

How to get httr POST request to work in R?

r

httr