rest_client Module
     __________________________________________________________

   Table of Contents

   1. Admin Guide

        1.1. Overview
        1.2. TCP Connection Reusage
        1.3. Dependencies

              1.3.1. OpenSIPS Modules
              1.3.2. External Libraries or Applications

        1.4. Exported Parameters

              1.4.1. curl_timeout (integer)
              1.4.2. connection_timeout (integer)
              1.4.3. connect_poll_interval (integer)
              1.4.4. max_async_transfers (integer)
              1.4.5. ssl_verifypeer (integer)
              1.4.6. ssl_verifyhost (integer)
              1.4.7. ssl_capath (integer)
              1.4.8. enable_expect_100 (boolean)

        1.5. Exported Functions

              1.5.1. rest_get(url, body_pv[, [ctype_pv][,
                      [retcode_pv]]])

              1.5.2. rest_post(url, send_body_pv, [send_ctype_pv],
                      recv_body_pv[, [recv_ctype_pv][,
                      [retcode_pv]]])

              1.5.3. rest_put(url, send_body_pv, [send_ctype_pv],
                      recv_body_pv[, [recv_ctype_pv][,
                      [retcode_pv]]])

              1.5.4. rest_append_hf(txt)
              1.5.5. rest_init_client_tls(tls_client_domain)

        1.6. Exported Asynchronous Functions

              1.6.1. rest_get(url, body_pv[, [ctype_pv][,
                      [retcode_pv]]])

              1.6.2. rest_post(url, send_body_pv, [send_ctype_pv],
                      recv_body_pv[, [recv_ctype_pv][,
                      [retcode_pv]]])

              1.6.3. rest_put(url, send_body_pv, [send_ctype_pv],
                      recv_body_pv[, [recv_ctype_pv][,
                      [retcode_pv]]])

   2. Contributors

        2.1. By Commit Statistics
        2.2. By Commit Activity

   3. Documentation

        3.1. Contributors

   List of Tables

   2.1. Top contributors by DevScore^(1), authored commits^(2) and
          lines added/removed^(3)

   2.2. Most recently active contributors^(1) to this module

   List of Examples

   1.1. Setting the curl_timeout parameter
   1.2. Setting the connection_timeout parameter
   1.3. Setting the connect_poll_interval parameter
   1.4. Setting the max_async_transfers parameter
   1.5. Setting the ssl_verifypeer parameter
   1.6. Setting the ssl_verifyhost parameter
   1.7. Setting the ssl_capath parameter
   1.8. Setting the enable_expect_100 parameter
   1.9. rest_get usage
   1.10. rest_post usage
   1.11. rest_put usage
   1.12. rest_append_hf usage
   1.13. rest_init_client_tls usage
   1.14. async rest_get usage
   1.15. async rest_post usage
   1.16. async rest_put usage

Chapter 1. Admin Guide

1.1. Overview

   The rest_client module provides a means of interacting with an
   HTTP server by doing RESTful queries, such as GET, POST and
   PUT.

1.2. TCP Connection Reusage

   Unless specified otherwise by the server through a "Connection:
   close" indication, the module will keep and reuse the TCP
   connections it creates as much as possible, regardless if the
   script writer performs blocking or asynchronous HTTP requests.
   These connections are not shared among OpenSIPS workers — each
   worker maintains its own set of connections.

1.3. Dependencies

1.3.1. OpenSIPS Modules

   The following modules must be loaded before this module:
     * No dependencies on other OpenSIPS modules..

1.3.2. External Libraries or Applications

   The following libraries or applications must be installed
   before running OpenSIPS with this module loaded:
     * libcurl.

1.4. Exported Parameters

1.4.1. curl_timeout (integer)

   The maximum allowed time for any HTTP(S) transfer to complete.
   This interval is inclusive of the initial connect time window,
   hence the value of this parameter must be greater than or equal
   to connection_timeout.

   Default value is “20” seconds.

   Example 1.1. Setting the curl_timeout parameter
...
modparam("rest_client", "curl_timeout", 10)
...

1.4.2. connection_timeout (integer)

   The maximum allowed time to establish a connection with the
   server.

   Default value is “20” seconds.

   Example 1.2. Setting the connection_timeout parameter
...
modparam("rest_client", "connection_timeout", 4)
...

1.4.3. connect_poll_interval (integer)

   Only relevant with async requests. Allows complete control over
   how quickly we want to detect libcurl's completed blocking
   TCP/TLS handshakes, so the async transfers can be put in the
   background. A lower connect_poll_interval may speed up all
   async HTTP transfers, but will also increase CPU usage.

   Default value is “20” milliseconds.

   Example 1.3. Setting the connect_poll_interval parameter
...
modparam("rest_client", "connect_poll_interval", 2)
...

1.4.4. max_async_transfers (integer)

   Maximum number of asynchronous HTTP transfers a single OpenSIPS
   worker is allowed to run simultaneously. As long as this
   threshold is reached for a worker, all new async transfers it
   attempts to perform will be done in a blocking manner, with
   appropriate logging warnings.

   Default value is “100”.

   Example 1.4. Setting the max_async_transfers parameter
...
modparam("rest_client", "max_async_transfers", 300)
...

1.4.5. ssl_verifypeer (integer)

   Set this to 0 in order to disable the verification of the
   remote peer's certificate. Verification is done using a default
   bundle of CA certificates which come with libcurl.

   Default value is “1” (enabled).

   Example 1.5. Setting the ssl_verifypeer parameter
...
modparam("rest_client", "ssl_verifypeer", 0)
...

1.4.6. ssl_verifyhost (integer)

   Set this to 0 in order to disable the verification that the
   remote peer actually corresponds to the server listed in the
   certificate.

   Default value is “1” (enabled).

   Example 1.6. Setting the ssl_verifyhost parameter
...
modparam("rest_client", "ssl_verifyhost", 0)
...

1.4.7. ssl_capath (integer)

   An optional path for CA certificates to be used for host
   verifications.

   Example 1.7. Setting the ssl_capath parameter
...
modparam("rest_client", "ssl_capath", "/home/opensips/ca_certificates")
...

1.4.8. enable_expect_100 (boolean)

   Include a "Expect: 100-continue" HTTP header field whenever the
   body size of a POST or PUT request exceeds 1024 bytes. Once
   enabled, the timeout for waiting for a "100 Continue" reply
   from the server is 1 second, after which the body upload will
   begin.

   Default value is “false” (disabled).

   Example 1.8. Setting the enable_expect_100 parameter
...
modparam("rest_client", "enable_expect_100", true)
...

1.5. Exported Functions

1.5.1.  rest_get(url, body_pv[, [ctype_pv][, [retcode_pv]]])

   Perform a blocking HTTP GET on the given url and return a
   representation of the resource.

   The body_pv pseudo-var will hold the body of the HTTP response.

   The optional ctype_pv pseudo-var will contain the value of the
   "Content-Type:" header of the response.

   The optional retcode_pv pseudo-var will retain the status code
   of the HTTP response. A 0 status code value means no HTTP reply
   arrived at all.

   Parameter Types
     * url - string, pseudo-variable or pseudo-variable format
       string
     * body_pv, ctype_pv, retcode_pv - pseudo-variables

   Return Codes
     * 1 - Success
     * -1 - Connection Refused.
     * -2 - Connection Timeout (the connection_timeout was
       exceeded before a TCP connection could be established)
     * -3 - Transfer Timeout (the curl_timeout was exceeded before
       the last byte was received). The retcode_pv may be set to
       200 or 0, depending whether a 200 OK was received or not.
       If it was, the body_pv will contain partially downloaded
       data, use at your own risk! (we recommend you only use this
       data for logging / debugging purposes)
     * -10 - Internal Error (out of memory, unexpected libcurl
       error, etc.)

   This function can be used from any route.

   Example 1.9. rest_get usage
...
# Example of querying a REST service to get the credit of an account
$var(rc) = rest_get("https://getcredit.org/?account=$fU",
                    "$var(credit)",
                    "$var(ct)",
                    "$var(rcode)");
if ($var(rc) < 0) {
        xlog("rest_get() failed with $var(rc), acc=$fU\n");
        send_reply("500", "Server Internal Error");
        exit;
}

if ($var(rcode) != 200) {
        xlog("L_INFO", "rest_get() rcode=$var(rcode), acc=$fU\n");
        send_reply("403", "Forbidden");
        exit;
}
...

1.5.2.  rest_post(url, send_body_pv, [send_ctype_pv], recv_body_pv[,
[recv_ctype_pv][, [retcode_pv]]])

   Perform a blocking HTTP POST on the given url. The request body
   will be copied from the send_body_pv pseudo-variable. The MIME
   Content-Type header for the request will be taken from
   send_ctype_pv (the default is
   "application/x-www-form-urlencoded")

   Note that the send_body_pv parameter can also accept a
   format-string but it cannot be larger than 1024 bytes. For
   larger messages, you must build them in a pseudo-variable and
   pass it to the function.

   The mandatory recv_body_pv pseudo-var will hold the body of the
   HTTP response.

   The optional recv_ctype_pv parameter will contain the value of
   the "Content-Type" header of the response.

   The optional retcode_pv pseudo-var will retain the status code
   of the HTTP response. A 0 status code value means no HTTP reply
   arrived at all.

   Parameter Types
     * url, send_body_pv, send_type_pv - string, pseudo-variable
       or pseudo-variable format string
     * body_pv, ctype_pv, retcode_pv - pseudo-variables

   Return Codes
     * 1 - Success
     * -1 - Connection Refused.
     * -2 - Connection Timeout (the connection_timeout was
       exceeded before a TCP connection could be established)
     * -3 - Transfer Timeout (the curl_timeout was exceeded before
       the last byte was received). The retcode_pv may be set to
       200 or 0, depending whether a 200 OK was received or not.
       If it was, the body_pv will contain partially downloaded
       data, use at your own risk! (we recommend you only use this
       data for logging / debugging purposes)
     * -10 - Internal Error (out of memory, unexpected libcurl
       error, etc.)

   This function can be used from any route.

   Example 1.10. rest_post usage
...
# Creating a resource using a RESTful service with an HTTP POST request
$var(rc) = rest_post("https://myserver.org/register_user",
                     "$fU", , "$var(body)", "$var(ct)", "$var(rcode)");
if ($var(rc) < 0) {
        xlog("rest_post() failed with $var(rc), user=$fU\n");
        send_reply("500", "Server Internal Error 1");
        exit;
}

if ($var(rcode) != 200) {
        xlog("rest_post() rcode=$var(rcode), user=$fU\n");
        send_reply("500", "Server Internal Error 2");
        exit;
}
...


1.5.3.  rest_put(url, send_body_pv, [send_ctype_pv], recv_body_pv[,
[recv_ctype_pv][, [retcode_pv]]])

   Perform a blocking HTTP PUT on the given url. The request body
   will be copied from the send_body_pv pseudo-variable. The MIME
   Content-Type header for the request will be taken from
   send_ctype_pv (the default is
   "application/x-www-form-urlencoded")

   Similar to rest_post(), the send_body_pv parameter can also
   accept a format-string but it cannot be larger than 1024 bytes.
   For larger messages, you must build them in a pseudo-variable
   and pass it to the function.

   The mandatory recv_body_pv pseudo-var will hold the body of the
   HTTP response.

   The optional recv_ctype_pv parameter will contain the value of
   the "Content-Type" header of the response message.

   The optional retcode_pv pseudo-var will retain the status code
   of the HTTP response. A 0 status code value means no HTTP reply
   arrived at all.

   Parameter Types
     * url, send_body_pv, send_type_pv - string, pseudo-variable
       or pseudo-variable format string
     * body_pv, ctype_pv, retcode_pv - pseudo-variables

   Return Codes
     * 1 - Success
     * -1 - Connection Refused.
     * -2 - Connection Timeout (the connection_timeout was
       exceeded before a TCP connection could be established)
     * -3 - Transfer Timeout (the curl_timeout was exceeded before
       the last byte was received). The retcode_pv may be set to
       200 or 0, depending whether a 200 OK was received or not.
       If it was, the body_pv will contain partially downloaded
       data, use at your own risk! (we recommend you only use this
       data for logging / debugging purposes)
     * -10 - Internal Error (out of memory, unexpected libcurl
       error, etc.)

   This function can be used from any route.

   Example 1.11. rest_put usage
...
# Creating/Updating a resource using a RESTful service with an HTTP PUT
request
$var(rc) = rest_put("https://myserver.org/users/$fU",
                    "$var(userinfo)", , "$var(body)", "$var(ct)", "$var(
rcode)");
if ($var(rc) < 0) {
        xlog("rest_put() failed with $var(rc), user=$fU\n");
        send_reply("500", "Server Internal Error 3");
        exit;
}

if ($var(rcode) != 200) {
        xlog("rest_put() rcode=$var(rcode), user=$fU\n");
        send_reply("500", "Server Internal Error 4");
        exit;
}
...

1.5.4.  rest_append_hf(txt)

   Append txt to the HTTP headers of the subsequent request.
   Multiple headers can be appended by making multiple calls
   before executing a request.

   The contents of txt should adhere to the specification for HTTP
   headers (ex. Field: Value)

   Parameter types
     * txt - String, pseudo-variable, or a String which includes
       pseudo-variables. (useful for specifying additional
       attribute-value fields in the URL)

   This function can be used from any route.

   Example 1.12. rest_append_hf usage
...
# Example of querying a REST service requiring additional headers

rest_append_hf("Authorization: Bearer mF_9.B5f-4.1JqM");
$var(rc) = rest_get("http://getcredit.org/?account=$fU", "$var(credit)")
;
...

1.5.5.  rest_init_client_tls(tls_client_domain)

   Force a specific TLS certificate and private key pair to be
   eventually used during the next request. Refer to the tls_mgm
   module for additional info regarding TLS client domains.

   If using this function, you must also ensure that tls_mgm is
   loaded and properly configured.

   Note that if you want to use this feature, the certificate must
   be provisioned in the configuration file, NOT in the database.
   In case you are loading TLS certificates from the database, you
   must at least define the default domain in the configuration
   script, where is currently the only place you can define it.

   Parameter types
     * tls_client_domain - string, pseudo-variable, or a string
       which includes pseudo-variables.

   This function can be used from any route.

   Example 1.13. rest_init_client_tls usage
...
rest_init_client_tls("1=10.11.12.13:3306");
if (!rest_get("https://example.com"))
    xlog("query failed\n");
...

1.6. Exported Asynchronous Functions

1.6.1.  rest_get(url, body_pv[, [ctype_pv][, [retcode_pv]]])

   Perform an asynchronous HTTP GET. This function behaves exactly
   the same as rest_get() (in terms of input, output and
   processing), but in a non-blocking manner. Script execution is
   suspended until the entire content of the HTTP response is
   available.

   Example 1.14. async rest_get usage
route {
        ...
        async(rest_get("http://getcredit.org/?account=$fU",
                       "$var(credit)", , "$var(rcode)"), resume);
}

route [resume] {
        $var(rc) = $rc;
        if ($var(rc) < 0) {
                xlog("async rest_get() failed with $var(rc), acc=$fU\n")
;
                send_reply("500", "Server Internal Error");
                exit;
        }

        if ($var(rcode) != 200) {
                xlog("L_INFO", "async rest_get() rcode=$var(rcode), acc=
$fU\n");
                send_reply("403", "Forbidden");
                exit;
        }

        ...
}

1.6.2.  rest_post(url, send_body_pv, [send_ctype_pv], recv_body_pv[,
[recv_ctype_pv][, [retcode_pv]]])

   Perform an asynchronous HTTP POST. This function behaves
   exactly the same as rest_post() (in terms of input, output and
   processing), but in a non-blocking manner. Script execution is
   suspended until the entire content of the HTTP response is
   available.

   Example 1.15. async rest_post usage
route {
        ...
        async(rest_post("http://myserver.org/register_user",
                        "$fU", , "$var(body)", "$var(ct)", "$var(rcode)"
), resume);
}

route [resume] {
        $var(rc) = $rc;
        if ($var(rc) < 0) {
                xlog("async rest_post() failed with $var(rc), user=$fU\n
");
                send_reply("500", "Server Internal Error 1");
                exit;
        }
        if ($var(rcode) != 200) {
                xlog("async rest_post() rcode=$var(rcode), user=$fU\n");
                send_reply("500", "Server Internal Error 2");
                exit;
        }

        ...
}


1.6.3.  rest_put(url, send_body_pv, [send_ctype_pv], recv_body_pv[,
[recv_ctype_pv][, [retcode_pv]]])

   Perform an asynchronous HTTP PUT. This function behaves exactly
   the same as rest_put() (in terms of input, output and
   processing), but in a non-blocking manner. Script execution is
   suspended until the entire content of the HTTP response is
   available.

   Example 1.16. async rest_put usage
route {
        ...
        async(rest_put("http://myserver.org/users/$fU", "$var(userinfo)"
, ,
                       "$var(body)", "$var(ct)", "$var(rcode)"), resume)
;
}

route [resume] {
        $var(rc) = $rc;
        if ($var(rc) < 0) {
                xlog("async rest_put() failed with $var(rc), user=$fU\n"
);
                send_reply("500", "Server Internal Error 3");
                exit;
        }
        if ($var(rcode) != 200) {
                xlog("async rest_put() rcode=$var(rcode), user=$fU\n");
                send_reply("500", "Server Internal Error 4");
                exit;
        }

        ...
}

Chapter 2. Contributors

2.1. By Commit Statistics

   Table 2.1. Top contributors by DevScore^(1), authored
   commits^(2) and lines added/removed^(3)
     Name DevScore Commits Lines ++ Lines --
   1. Liviu Chircu (@liviuchircu) 116 63 3255 1461
   2. Ionut Ionita (@ionutrazvanionita) 23 12 663 262
   3. Razvan Crainea (@razvancrainea) 14 12 40 16
   4. Bogdan-Andrei Iancu (@bogdan-iancu) 6 4 95 47
   5. Vlad Patrascu (@rvlad-patrascu) 6 4 55 1
   6. Jarrod Baumann (@jarrodb) 6 3 131 32
   7. Agalya Ramachandran (@AgalyaR) 6 2 354 1
   8. Ryan Bullock (@rrb3942) 5 2 91 77
   9. Andrey Vorobiev (@andrey-vorobiev) 2 1 4 0

   (1) DevScore = author_commits + author_lines_added /
   (project_lines_added / project_commits) + author_lines_deleted
   / (project_lines_deleted / project_commits)

   (2) including any documentation-related commits, excluding
   merge commits. Regarding imported patches/code, we do our best
   to count the work on behalf of the proper owner, as per the
   "fix_authors" and "mod_renames" arrays in
   opensips/doc/build-contrib.sh. If you identify any
   patches/commits which do not get properly attributed to you,
   please submit a pull request which extends "fix_authors" and/or
   "mod_renames".

   (3) ignoring whitespace edits, renamed files and auto-generated
   files

2.2. By Commit Activity

   Table 2.2. Most recently active contributors^(1) to this module
                     Name                   Commit Activity
   1. Vlad Patrascu (@rvlad-patrascu)     May 2017 - Jun 2020
   2. Liviu Chircu (@liviuchircu)         Mar 2013 - Apr 2020
   3. Razvan Crainea (@razvancrainea)     Aug 2015 - Nov 2019
   4. Bogdan-Andrei Iancu (@bogdan-iancu) Oct 2014 - Jun 2018
   5. Ionut Ionita (@ionutrazvanionita)   Feb 2017 - Mar 2017
   6. Andrey Vorobiev (@andrey-vorobiev)  Feb 2017 - Feb 2017
   7. Ryan Bullock (@rrb3942)             Jan 2017 - Jan 2017
   8. Agalya Ramachandran (@AgalyaR)      Oct 2016 - Oct 2016
   9. Jarrod Baumann (@jarrodb)           Apr 2015 - May 2015

   (1) including any documentation-related commits, excluding
   merge commits

Chapter 3. Documentation

3.1. Contributors

   Last edited by: Liviu Chircu (@liviuchircu), Bogdan-Andrei
   Iancu (@bogdan-iancu), Razvan Crainea (@razvancrainea), Agalya
   Ramachandran (@AgalyaR), Jarrod Baumann (@jarrodb).

   doc copyrights:

   Copyright © 2013 www.opensips-solutions.com
