Download file using REST API

[Rj27]

Hi All,

I need to download files attached to any incident using REST API.

I will be sending incident detail from my postman. 

Already Referred to attachment api reference docs but could'nt find a solution.

NOTE: I don't have the option to use ui action 

Is this doable?

Thanks in Advance!

[Rj27]

Hi Hozawa,

Thanks for the link. Checking the same.

Do let me know if it works for you.

Thanks!

[Pradeep Sharma]

Hi RJ,

I tried below CURL command through POST man and I am able to download the file directly on my machine. 

Details below.

https://developer.servicenow.com/dev.do#!/reference/api/orlando/rest/c_AttachmentAPI

curl "https://instance.service-now.com/api/now/attachment/615ea769c0a80166001cf5f2367302f5/file" \
--request GET \
--header "Accept:*/*" \
--user 'admin':'admin'

[Rj27]

Hi Pradeep,

Thanks for the response.
In the curl command above, is this the sys id of the attachment? If yes, then it's not feasible to give sys id i guess if we consider from end user's perspective.

Also, there's a possibility there can be multiple attachments in a single incident . So it's i guess giving sys id everytime will not work.

[Hitoshi Ozawa]

Other API calls are required to fetch the sys_id before this. There isn't a single API to fetch the attachments.

[Hitoshi Ozawa]

@Rj27 

Following is a python3 script to download attachments of a Knowledge Base article given a knowledge article number

import requests

from servicenowapis.constants import ATTACHMENT_API, DOWNLOAD_DIR, REQUEST_HEADER,\
    SERVICENOW_PWD, SERVICENOW_URL,SERVICENOW_USER, TABLE_API


def get_table_data(table_name, param):
    url = SERVICENOW_URL + '/' + TABLE_API + '/' + table_name + '?' + param
    response = requests.get(url, auth=(SERVICENOW_USER, SERVICENOW_PWD), headers=REQUEST_HEADER.get('json'))
    if response.status_code != 200: # if error, then exit
        print('Status:', response.status_code, 'Headers:', response.headers, 'Error Response:', response.json())
        exit()
    return response.json()


def get_attachment_info(sys_id):
    url = SERVICENOW_URL + ATTACHMENT_API + '/' + sys_id
    response = requests.get(url, auth=(SERVICENOW_USER, SERVICENOW_PWD), headers=REQUEST_HEADER.get('json'))
    if response.status_code != 200:  # if error, then exit
        print(f'Status:  {response.status_code}, Headers:{response.headers}')
        exit()
    return response.json()


def get_attachment(att_sys_id, file_type, download_dir):
    url = SERVICENOW_URL + '/' + ATTACHMENT_API + '/' + att_sys_id + '/file'
    response = requests.get(url, auth=(SERVICENOW_USER, SERVICENOW_PWD), headers=REQUEST_HEADER.get(file_type))
    if response.status_code != 200:  # if error, then exit
        print('Status:', response.status_code, 'Headers:', response.headers, 'Error Response:', response.json())
        exit()
    with open(download_dir, 'wb') as f:
        for chunk in response:
            f.write(chunk)


def get_kb_attachment(kb_number):
    param = 'sysparm_query=number=' + kb_number + '&sysparam_limit=1'
    kb_info = get_table_data('kb_knowledge', param)
    kb_sys_id = kb_info.get('result')[0].get('sys_id')

    param = 'sysparm_query=table_sys_id=' + kb_sys_id + '&sysparam_limit=1'
    kb_attachments = get_table_data('sys_attachment', param)
    result = kb_attachments.get('result')
    for attach_file in result:
        attach_sys_id = attach_file.get('sys_id')
        content_type = attach_file.get('content_type').split('/')
        file_ext = content_type[1]
        file_name = attach_file.get('file_name')
        get_attachment(attach_sys_id, file_ext, DOWNLOAD_DIR + file_name)


if __name__ == '__main__':
    get_kb_attachment('<kb article number>')  # knowledge base number e.g.KB0010062

constants.py

SERVICENOW_URL = 'https://<instance>.service-now.com'
SERVICENOW_USER = 'username'
SERVICENOW_PWD = 'password'

DOWNLOAD_DIR = 'C:/Users/hozawa/downloads/'

REQUEST_HEADER = {"json": {"Content-Type": "application/xml", "Accept": "application/json"},
                  "png": {"Content-Type": "application/xml", "Accept": "application/png"},
                  "xml": {"Content-Type": "application/xml", "Accept": "application/xml"},
                  }

ATTACHMENT_API = '/api/now/attachment'
TABLE_API = '/api/now/table'