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.

In Warp 10 2.x, there was 3 ways to perform HTTP requests in WarpScript or FLoWS.

Update: Since Warp 10 3.0, there is only one way : the HTTP function.

HTTP

HTTP allows you to send a GET or POST HTTP request (thanks Captain Obvious), waiting for a response.

Among the different options, you can even stream your data using the chunks.

Following Warp 10 3.0 trend, most of the configurations can be superseeded by capabilities.

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.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 a comma separated list of regular expression like slack.com,.*!

WarpScript

First, you need to generate a token to be able to use HTTP: create a mc2 file with this content

{
  'id' 'TokenRead'
  'type' 'READ'
  'application' 'nonexistingapp' 
  'owner'  "c7636029-d7b5-4b7a-9aab-65d61419d719"
  'issuance' 0
  'expiry' [ 2200 01 01 ] TSELEMENTS->
  'labels' { }   
  'attributes' { 
    '.cap:http' 'localhost,127.0.0.1,api.mysite.fr'        // able to use HTTP
    '.cap:http.requests' '100000' // number of HTTP call allowed per script
    '.cap:http.size' '100000000' // raise HTTP download limit to 100MB
    '.cap:http.chunksize' '1000000' // raise HTTP size chunk to 1MB
  } 
  'applications' [ 'nonexistingapp' ]  
} TOKENGEN

Run it. By default, TOKENGEN is not accessible, so you need an access to the server to run /opt/warp10/bin/warp10.sh tokengen /path/to/this/file.mc2

Then you can use the generated token in your script with CAPADD, to enjoy HTTP!

'tokenWithHttpCapability' CAPADD
{
 '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

WEBCALL (deprecated)

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

URLFETCH (deprecated)

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

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