Hands on with cURL: client for URLs

This lab exercise will get you started with RESTCONF connections, retrieving data, and sending configurations to the network.

Understanding cURL:

The cURL name is a play on words: “Client for URLs” and “cURL URL Request Library.” It’s a simple command-line tool with lots of options for putting together a REST API request.

When using cURL to make REST API method calls, you typically use the following options and arguments:

• -X followed by a request verb such as GET, PUT, POST, PATCH, or DELETE.
• -H followed by a header such as a token to send with the requests.

For example, a GET request is often used to get a list or to get details about a single resource. So lets walk through an example,

Step 1: Use cURL for RESTCONF configuration

1. The following is a sample RESTCONF request to router to check the allowed methods available for restconf configurations

curl -i -k -X "OPTIONS" "https://10.0.0.1:443/restconf/data/Cisco-IOS-XE-native:native/logging/monitor/severity" -H 'Accept: application/yang-data+json' -u 'cisco:cisco'

2. The router will reply with allowed methods available for RESTCONF.

< HTTP/1.1 200 OK
Server: nginx
Date: Wed, 29 Apr 2020 12:40:50 GMT
Content-Type: text/html
Content-Length: 0
Connection: keep-alive
Allow: DELETE, GET, HEAD, PATCH, POST, PUT, OPTIONS
Cache-Control: private, no-cache, must-revalidate, proxy-revalidate
Accept-Patch: application/yang-data+xml, application/yang-data+json
Pragma: no-cache

3. The following is a sample RESTCONF request to get primary ip address details of configured GigabitEthernet interfaces.

curl -i -k -X "GET" "https://10.0.0.1:443/restconf/data/Cisco-IOS-XE-native:native/interface?fields=GigabitEthernet/ip/address/primary;name" -H 'Accept: application/yang-data+json' -u 'cisco:cisco'

4. The router will reply with allowed methods available for RESTCONF.

HTTP/1.1 200 OK
Server: nginx
Date: Wed, 29 Apr 2020 14:03:46 GMT
Content-Type: application/yang-data+json
Transfer-Encoding: chunked
Connection: keep-alive
Cache-Control: private, no-cache, must-revalidate, proxy-revalidate
Pragma: no-cache

{
  "Cisco-IOS-XE-native:interface": {
    "GigabitEthernet": [
      {
        "ip": {
          "address": {
            "primary": {
              "address": "10.0.0.1",
              "mask": "255.255.255.0"
            }
          }
        }
      },
      {
        "ip": {
          "address": {
            "primary": {
              "address": "10.255.255.1",
              "mask": "255.255.255.0"
            }
          }
        }
      }
    ]
  }
}

5. The following is a sample RESTCONF request to get ip address details of interface GigabitEthernet 2.

curl -i -k -X "GET" "https://10.0.0.1:443/restconf/data/Cisco-IOS-XE-native:native/interface/GigabitEthernet=2/ip" -H 'Accept: application/yang-data+json' -u 'cisco:cisco'

6. The router will reply with allowed methods available for RESTCONF.

HTTP/1.1 200 OK
Server: nginx
Date: Wed, 29 Apr 2020 14:17:34 GMT
Content-Type: application/yang-data+json
Transfer-Encoding: chunked
Connection: keep-alive
Cache-Control: private, no-cache, must-revalidate, proxy-revalidate
Pragma: no-cache

{
  "Cisco-IOS-XE-native:ip": {
    "address": {
      "secondary": [
        {
          "address": "200.0.0.200",
          "mask": "255.0.0.0",
          "secondary": [null]
        }
      ],
      "primary": {
        "address": "10.255.255.1",
        "mask": "255.255.255.0"
      }
    }
  }
}

7. The following is a sample RESTCONF request to get primary ip address of interface GigabitEthernet 1.

curl -i -k -X "GET" "https://10.0.0.1:443/restconf/data/Cisco-IOS-XE-native:native/interface/GigabitEthernet=1/ip/address/primary" -H 'Accept: application/yang-data+json' -u 'cisco:cisco'

8. The router will reply with allowed methods available for RESTCONF.

HTTP/1.1 200 OK
Server: nginx
Date: Wed, 29 Apr 2020 14:19:28 GMT
Content-Type: application/yang-data+json
Transfer-Encoding: chunked
Connection: keep-alive
Cache-Control: private, no-cache, must-revalidate, proxy-revalidate
Pragma: no-cache

{
  "Cisco-IOS-XE-native:primary": {
    "address": "10.0.0.1",
    "mask": "255.255.255.0"
  }
}

9. The following is a sample RESTCONF request to change hostname.

curl -i -k -X  PUT https://10.0.0.1/restconf/data/Cisco-IOS-XE-native:native/hostname -H 'Accept: application/yang-data+json' -H 'Content-Type: application/yang-data+json' -H 'cache-control: no-cache' -u 'cisco:cisco' -d '{"hostname": "HelloRST"}'

10. The following is a sample RESTCONF request to change Loopback ip address

curl -i -k -X PATCH https://10.0.0.1/restconf/data/Cisco-IOS-XE-native:native/interface/Loopback=1/ip/address/primary -H 'Accept: application/yang-data+json' -H 'Content-Type: application/yang-data+json' -H 'cache-control: no-cache' -u 'cisco:cisco' -d '{"primary": {"address": "1.1.1.1", "mask": "255.255.255.0"}}' 

Step 2: Python for RESTCONF configuration

1. The following is a sample RESTCONF request in python to get IP address of loopback 1 interface.

import requests
import urllib3

USER = 'cisco'
PASS = 'cisco'

# disable warnings from SSL/TLS certificates
requests.packages.urllib3.disable_warnings()

url = "https://10.0.0.1/restconf/data/Cisco-IOS-XE-native:native/interface/Loopback=1/ip/address/primary"

headers = {
    'Accept': "application/yang-data+json",
    'Content-Type': "application/yang-data+json",
    'cache-control': "no-cache",
    }

response = requests.get(url, auth=(USER, PASS),
                            headers=headers, verify=False)
print(response.text)

2. The router will reply as below.

From cffi callback <function _verify_callback at 0x7f4be07c61d0>:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/OpenSSL/SSL.py", line 315, in wrapper
    _lib.X509_up_ref(x509)
AttributeError: 'module' object has no attribute 'X509_up_ref'
{
  "Cisco-IOS-XE-native:primary": {
    "address": "100.200.200.200",
    "mask": "255.255.255.0"
  }
}

3. The following is a sample RESTCONF request in python to get hostname of router.

import requests
import urllib3

USER = 'cisco'
PASS = 'cisco'

# disable warnings from SSL/TLS certificates
requests.packages.urllib3.disable_warnings()

url = "https://10.0.0.1/restconf/data/Cisco-IOS-XE-native:native/hostname"

payload = ""
headers = {
    'Accept': "application/yang-data+json",
    'Content-Type': "application/yang-data+json",
    'cache-control': "no-cache",
    }

print("----------------------")
print("RSTForum- Configuration Parameters:")
print("----------------------")
response = requests.request("GET",url, auth=(USER, PASS), data=payload,
                            headers=headers, verify=False)

print(response.text)
print("----------------------")
print("RSTForum- Thanks you:")
print("----------------------")

4. The router will reply as below.

From cffi callback <function _verify_callback at 0x7f87a2192050>:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/OpenSSL/SSL.py", line 315, in wrapper
    _lib.X509_up_ref(x509)
AttributeError: 'module' object has no attribute 'X509_up_ref'
{
  "Cisco-IOS-XE-native:hostname": "RSTForum"
}

5. The following is a sample RESTCONF request in python to post Loopback Ip address.

import requests
import urllib3

USER = 'cisco'
PASS = 'cisco'

# disable warnings from SSL/TLS certificates
requests.packages.urllib3.disable_warnings()

url = "https://10.0.0.1/restconf/data/Cisco-IOS-XE-native:native/interface/Loopback=1/ip/address/primary"

payload = "{\"primary\": {\"address\": \"88.88.88.88\", \"mask\": \"255.255.255.0\"}}"
headers = {
    'Accept': "application/yang-data+json",
    'Content-Type': "application/yang-data+json",
    'cache-control': "no-cache",
    }

print("----------------------")
print("RSTForum- Configuration Parameters:")
print("----------------------")
response = requests.request("PATCH",url, auth=(USER, PASS), data=payload,
                            headers=headers, verify=False)

print(response.text)
print("----------------------")
print("RSTForum- Thanks you:")
print("----------------------")

6. The router will reply as below.

From cffi callback <function _verify_callback at 0x7fa0034951d0>:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/OpenSSL/SSL.py", line 315, in wrapper
    _lib.X509_up_ref(x509)
AttributeError: 'module' object has no attribute 'X509_up_ref'

7. The following is a sample RESTCONF request in python to put hostname.

import requests
import urllib3

USER = 'cisco'
PASS = 'cisco'

# disable warnings from SSL/TLS certificates
requests.packages.urllib3.disable_warnings()

url = "https://10.0.0.1/restconf/data/Cisco-IOS-XE-native:native/hostname"

payload = "{\"hostname\": \"RSTForum\"}"
headers = {
    'Accept': "application/yang-data+json",
    'Content-Type': "application/yang-data+json",
    'cache-control': "no-cache",
    }

8. The router will reply as below.

From cffi callback <function _verify_callback at 0x7fe88bf8d050>:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/OpenSSL/SSL.py", line 315, in wrapper
    _lib.X509_up_ref(x509)
AttributeError: 'module' object has no attribute 'X509_up_ref'