3 ways to perform HTTP requests

Often we need to perform HTTP requests in our scripts, for instance, to send a notification in a Slack channel or to a mailing API, to fetch data from a REST API or to send data to a tier server.

There are 3 ways to perform HTTP requests in WarpScript or FLoWS.

WEBCALL

WEBCALL is historically the first one. It allows you to send an HTTP request without waiting for a response. This is a one-way action. WEBCALL is handy to notify an HTTP Server without slowing your code execution or introducing a bottleneck.

Configuration parameters in /path/to/warp10/etc/conf.d/10-webcall.conf:

• webcall.host.patterns: allow/disallow some hosts based on regular expression like slack.com,!^127.0.0.1$,!^localhost$,^192.168.*
• warpscript.maxwebcalls: maximum parallel usage
• http.header.webcall.uuid:  will appear in the X-Warp10-WebCall header
• webcall.user.agent: "Warp10-WebCall" by default

WarpScript

'9M8DP97xxxxxxZwKm78zc' // WRITE token
'POST'
'https://hooks.slack.com/services/T01xxxxNT1/B0xxxM/bzZxxx5yHdJJ'
{ 'Content-Type' 'application/json' } // HTTP headers
{
  'channel' '#alertes'
  'username' 'Warp 10'
  'text' "Published in #alertes from user Warp 10."
  'icon_emoji' ':spock-hand:'
} ->JSON // Payload
WEBCALL

FLoWS

payload = ->JSON({
  "channel": "#alertes",
  "username": "Warp 10",
  "text": "Published in #alertes from user Warp 10.",
  "icon_emoji": ":spock-hand:"
})

return WEBCALL(
  "9M8DP97xxxxxxZwKm78zc", // WRITE token
  "POST",
  "https://hooks.slack.com/services/T01xxxxNT1/B0xxxM/bzZxxx5yHdJJ",
  { "Content-Type": "application/json" },
  payload
)

URLFETCH

URLFETCH allows you to perform a GET request and give you back the response, headers and status. It could be a bottleneck in your code, because it waits for the response.

For security reasons, you must be authenticated with a READ token.

By the way, this function will be deprecated in a future Warp 10 version because replaced by HTTP.

Configuration parameters in /path/to/warp10/etc/conf.d/70--extensions.conf:

• warpscript.extension.urlfetch = io.warp10.script.ext.urlfetch.UrlFetchWarpScriptExtension: Activate the extension
• warpscript.urlfetch.limit: maximum parallel usage a developer can bypass
• warpscript.urlfetch.limit.hard: maximum parallel usage
• warpscript.urlfetch.maxsize: maximum response size a developer can bypass
• warpscript.urlfetch.maxsize.hard: maximum response size
• warpscript.urlfetch.host.patterns: allow/disallow some hosts based on regular expression like slack.com,.*!

WarpScript

'oQ4t3FJSguxxxxxxxxxxUCXo3vvRGg0Q5.'  // READ token
AUTHENTICATE

'https://random-data-api.com/api/name/random_name?size=5' URLFETCH 0 GET 3 GET // get body
B64-> 'utf8' BYTES-> JSON-> // decode as JSON
<% 'name' GET %> F LMAP

FLoWS

AUTHENTICATE('oQ4t3FJSguxxxxxxxxxxUCXo3vvRGg0Q5.')

response = URLFETCH('https://random-data-api.com/api/name/random_name?size=5')
body = JSON->(BYTES->(B64->(response[0][3]), 'utf8')) // extract body as JSON
return LMAP(body, (item)-> { return item['name'] }, false)

HTTP

HTTP allows you to send an HTTP request (thanks Captain Obvious), waiting for a response but with more options than URLFETCH, especially, you can specify the method.

One more important think, you can even stream your data using the chunks.

Configuration parameters in /path/to/warp10/etc/conf.d/70--extensions.conf:

• warpscript.extension.http=io.warp10.script.ext.http.HttpWarpScriptExtension: Activate the extension
• warpscript.http.authentication.required: allows you to bypass the authentification process (which is mandatory for URLFETCH)
• warpscript.http.capability: Token capabilities handling
• warpscript.http.maxrequests: maximum parallel usage
• warpscript.http.maxsize: maximum response size
• warpscript.http.maxchunksize: maximum chunk size
• warpscript.http.host.patterns: allow/disallow some hosts based on regular expression like slack.com,.*!

WarpScript

{
 'url' 'https://hooks.slack.com/services/T01xxxxNT1/B0xxxM/bzZxxx5yHdJJ'
 'method' 'POST'
 'headers' { 'Content-Type' 'application/json' }
 'body' {
   'channel' '#alertes'
   'username' 'Warp 10'
   'text' "Published in #alertes from user Warp 10."
   'icon_emoji' ':spock-hand:'
 } ->JSON
}
HTTP

FLoWS

return HTTP({
  "url": "https://hooks.slack.com/services/T01xxxxNT1/B0xxxM/bzZxxx5yHdJJ",
  "method": "POST",
  "headers": { "Content-Type": "application/json" },
  "body": '{
    "channel": "#alertes",
    "username": "Warp 10",
    "text": "Published in #alertes from user Warp 10.",
    "icon_emoji" ":spock-hand:"
  }'
})

Going further

You can now access external APIs and make Warp 10 dialog with your stack.

To simplify your usage, you can develop macros to embed those calls in order to factorize and control your code.

Xavier Marin

Senior Software Engineer