Json Question posted in
Our archive of expertly curated questions and answers provides insights and solutions to common problems related to this popular data interchange format. From parsing and manipulating JSON data to integrating it with various programming languages and web services, our archive has got you covered. Start exploring today and take your JSON skills to the next level

R Parsing output from JSON API

I want to retrieve data from IMF JSON RESTful Web Service API. I have found a dataset name and series code, so I submit a following request, usinng httr2 pacakge:

library(httr2)
library(tidyverse)
req <- request("http://dataservices.imf.org/REST/SDMX_JSON.svc/CompactData/IFS/PCPI_IX?startPeriod=2015&endPeriod=2020") %>% 
  req_perform()

As a result I get a list of 7 items.

How should I parse this output to get actual data? In the body item in the response there’re no actual numbers. I’ve tried to use fromJSON from the jsonlite library but it gives me an error (Argument ‘txt’ must be a JSON string, URL or file).

library(jsonlite)
req <- request("http://dataservices.imf.org/REST/SDMX_JSON.svc/CompactData/IFS/PCPI_IX?startPeriod=2015&endPeriod=2020") %>% 
  req_perform() %>% 
  fromJSON()
Tags:

2

Answers


  1. 0

    You can use httr instead:

    library(httr)
library(jsonlite)

res <- GET("http://dataservices.imf.org/REST/SDMX_JSON.svc/CompactData/IFS/PCPI_IX?startPeriod=2015&endPeriod=2020")

data <- content(res, as = "text", encoding = "UTF-8")

data_list <- fromJSON(data)

data_list

$CompactData
$CompactData$`@xmlns:xsi`
[1] "http://www.w3.org/2001/XMLSchema-instance"

$CompactData$`@xmlns:xsd`
[1] "http://www.w3.org/2001/XMLSchema"

$CompactData$`@xsi:schemaLocation`
[1] "http://www.SDMX.org/resources/SDMXML/schemas/v2_0/message https://registry.sdmx.org/schemas/v2_0/SDMXMessage.xsd http://dataservices.imf.org/compact/IFS http://dataservices.imf.org/compact/IFS.xsd"

$CompactData$`@xmlns`
[1] "http://www.SDMX.org/resources/SDMXML/schemas/v2_0/message"

$CompactData$Header
$CompactData$Header$ID
[1] "793c6858-2fb3-4af1-9612-637fd135ad32"

$CompactData$Header$Test
[1] "false"

$CompactData$Header$Prepared
[1] "2024-12-03T07:30:41"

$CompactData$Header$Sender
$CompactData$Header$Sender$`@id`
[1] "1C0"

$CompactData$Header$Sender$Name
$CompactData$Header$Sender$Name$`@xml:lang`
[1] "en"

$CompactData$Header$Sender$Name$`#text`
[1] "IMF"

$CompactData$Header$Sender$Contact
$CompactData$Header$Sender$Contact$URI
[1] "http://www.imf.org"

$CompactData$Header$Sender$Contact$Telephone
[1] "+ 1 (202) 623-6220"

$CompactData$Header$Receiver
$CompactData$Header$Receiver$`@id`
[1] "ZZZ"

$CompactData$Header$DataSetID
[1] "IFS"

$CompactData$DataSet
$CompactData$DataSet$`@xmlns`
[1] "http://dataservices.imf.org/compact/IFS"
    Login or Signup to reply.
  2. 0

    There is no need to switch to {httr}

    httr is superseded: only changes necessary to keep it on CRAN will be
    made. We recommend using httr2 instead.

    Source: https://httr.r-lib.org/

    You can use httr2::resp_body_json

    library(httr2)
req <- request("http://dataservices.imf.org/REST/SDMX_JSON.svc/CompactData/IFS/PCPI_IX?startPeriod=2015&endPeriod=2020")
resp <- req |> req_perform()
parsed_body <- resp_body_json(resp)
parsed_body

    Please see this related article.

    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search