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Introduction#

Version 2021.08.0

This guide contains recipes for interacting with the Connect Server API from code. The recipes are intended to be straightforward enough to be implemented in any programming language you wish to use.

Getting Started#

You will need:

  • The URL for your RStudio Connect server
  • An RStudio Connect API Key for your account on the server

Your RStudio Connect server URL is the same URL you use to access the RStudio Connect dashboard, minus the connect path. If you access the dashboard at https://rsc.company.com/connect/, the server URL is https://rsc.company.com/.

The API Keys chapter of the RStudio Connect User Guide explains how to provision an RStudio Connect API Key. We recommend that you create an RStudio Connect API Key for each unique application that needs API access to RStudio Connect.

Once you've provisioned an RStudio Connect API Key, use environment variables to obtain the RStudio Connect server URL and API Key. Environment variables keep the literal URL and Key values from your source code, meaning you can share that code without worrying about accidentally sharing your RStudio Connect API Key.

Environments and Environment Variables#

Configuring your RStudio Connect server URL and API Key with environment variables gives you quite a bit of flexibility when deploying your code into different RStudio Connect servers running in different environments.

Code that uses Sys.getenv to load the server URL and API Key can be used in development, staging, or production environments. The same code can run in all three environments.

Use .Renviron files to configure environment variables in development.

Here is a sample .Renviron file that you can use in your development environment. It defines RStudio Connect the server URL and API Key you use while developing. The .Renviron file is loaded by every R session spawned under your user account.

# ~/.Renviron
# The CONNECT_SERVER URL must have a trailing slash.
CONNECT_SERVER="https://rsc.company.com/"
CONNECT_API_KEY="mysupersecretapikey"

Your code will obtain the RStudio Connect server URL and API Key from the environment. The Sys.getenv function lets us load environment variables in R.

connectServer <- Sys.getenv("CONNECT_SERVER")
connectAPIKey <- Sys.getenv("CONNECT_API_KEY")

Give these environment variables values when code is deployed to RStudio Connect. The "Vars" tab in the RStudio Connect dashboard lets you configure environment variables for each piece of content. The Environment Variables section of the RStudio Connect User Guide discusses how to use the "Vars" tab to configure environment variables.

Sticky Sessions#

RStudio Connect can be deployed with multiple instances in a highly available, load-balanced configuration. The load balancer routing traffic to these RStudio Connect servers must be configured with sticky sessions using session cookies.

Info

The High Availability and Load Balancing chapter of the RStudio Connect Admin Guide provides details about running a cluster of RStudio Connect instances.

Sticky Session cookies are returned by the load balancer to a client with the first HTTP response. The client adds that cookie to all subsequent requests. The load balancer uses session cookies to determine what server should receive the incoming request.

RStudio Connect needs sticky sessions so requests from the same client can be routed to the same server. This is how your browser maintains connectivity to the server running a Shiny application on your behalf.

curl#

The curl command-line utility can use an on-disk cookie jar to receive and send HTTP cookies, including those used for sticky sessions. The -c and --cookie-jar options tell curl to write cookies to the named file. The -b and --cookie options tell curl to read cookies from that file.

#
# Write cookies from our first request.
curl -c cookie-jar.txt \
    -H "Authorization: Key ${CONNECT_API_KEY}" \
    "http://rsc.company.com/content/24/mean?samples=5"
# Use those session cookies later.
curl -b cookie-jar.txt \
    -H "Authorization: Key ${CONNECT_API_KEY}" \
    "http://rsc.company.com/content/24/mean?samples=5"

The Cookies chapter of the Everything curl book has more information about using cookies with curl.

R with httr#

The httr R package automatically maintains cookies across requests within an R session; no additional code is needed.

library(httr)

connectServer <- Sys.getenv("CONNECT_SERVER")
connectAPIKey <- Sys.getenv("CONNECT_API_KEY")

# The initial request in an R session will have no HTTP session cookies.
resp <- httr::GET(connectServer, 
  path = "/content/24/mean",
  query = list(samples = 5),
  add_headers(Authorization = paste("Key", connectAPIKey))
)
# ...

# Later requests retain cookies set by the previous request.
resp <- httr::GET(connectServer, 
  path = "/content/24/mean",
  query = list(samples = 10),
  add_headers(Authorization = paste("Key", connectAPIKey))
)
# ...

Python2 with urllib2#

The cookielib module is part of the Python2 standard library. This is a basic example that retains cookies in-memory within a Python process.

import cookielib
import os
import urllib
import urllib2
import urlparse

connect_server = os.getenv("CONNECT_SERVER")
connect_api_key = os.getenv("CONNECT_API_KEY")

def build_url(base, path, **kwargs):
    query = urllib.urlencode(kwargs)
    parts = urlparse.urlparse(base)
    parts = parts._replace(path = path, query = query)
    return parts.geturl()

jar = cookielib.CookieJar()
processor = urllib2.HTTPCookieProcessor(jar)
opener = urllib2.build_opener(processor)

headers = { "Authorization": "Key %s" % connect_api_key }

# The initial request using the cookie jar will have no HTTP session cookies.
request_url = build_url(connect_server, "/content/24/mean", samples = 5)
request = urllib2.Request(request_url, headers = headers)
response = opener.open(request)
# ...

# Later requests retain cookies set by the previous request.
request_url = build_url(connect_server, "/content/24/mean", samples = 10)
request = urllib2.Request(request_url, headers = headers)
response = opener.open(request)
# ...

Python3 with urllib#

The http.cookiejar package is part of the Python3 standard library. This is a basic example that retains cookies in-memory within a Python process.

import http.cookiejar
import json
import os
import urllib.parse
import urllib.request

connect_server = os.getenv("CONNECT_SERVER")
connect_api_key = os.getenv("CONNECT_API_KEY")

def build_url(base, path, **kwargs):
    query = urllib.parse.urlencode(kwargs)
    parts = urllib.parse.urlparse(base)
    parts = parts._replace(path = path, query = query)
    return parts.geturl()

jar = http.cookiejar.CookieJar()
processor = urllib.request.HTTPCookieProcessor(jar)
opener = urllib.request.build_opener(processor)

headers = { "Authorization": "Key %s" % connect_api_key }

# The initial request using the cookie jar will have no HTTP session cookies.
request_url = build_url(connect_server, "/content/24/mean", samples = 5)
request = urllib.request.Request(request_url, headers = headers)
response = opener.open(request)
# ...

# Later requests retain cookies set by the previous request.
request_url = build_url(connect_server, "/content/24/mean", samples = 10)
request = urllib.request.Request(request_url, headers = headers)
response = opener.open(request)
# ...