Download attachment by passing file_name instead of sys_id

[Ovin Detree]

We are able to download an attachment using the sys id by using the below URL in the web browser or postman.

https://servicenow-instance.ourdomain.com/sys_attachment.do?sys_id=21e63dce1fbec118fb5252c7b04cbcd4

Can we download an attachment by querying just with the filename?

I tried: https://servicenow-instance.ourdomain.com/sys_attachment.do?file_name=myfile.xls but it didn't work.

Thanks in advance.

[Hitoshi Ozawa]

Following is an example Scripted API to download file attached to an incident.

Query Parameters are "number" (incident number) and "filename" (name of attached file).

Scripted API

(function process( /*RESTAPIRequest*/ request, /*RESTAPIResponse*/ response) {

    var tableName = 'incident';

    var queryParams = request.queryParams;
    var number = queryParams.number.toString();
    var filename = queryParams.filename.toString();

    try {
        var grTable = new GlideRecord(tableName);
        if (grTable.get('number', number)) {
            var grAttach = new GlideRecord('sys_attachment');
            grAttach.addQuery('table_sys_id', grTable.sys_id);
            if (filename && filename.length > 0) {
                grAttach.addQuery('file_name', filename);
            }
            grAttach.query();
            if (grAttach.next()) {
                filename = grAttach.file_name;
                var content_type = grAttach.content_type;
                var created = grAttach.created;
                var created_by = grAttach.created_by;

                var file_ext = content_type.substr(content_type.lastIndexOf('/') + 1);
                var hdrs = {},
                    attachment_sys_id = filename + file_ext;
                hdrs['Content-Type'] = content_type;

                response.setStatus(200);
                response.setHeaders(hdrs);

                var writer = response.getStreamWriter();
                var attachmentStream = new GlideSysAttachmentInputStream(grAttach.sys_id);
                writer.writeStream(attachmentStream);
            }
        }
    } catch (e) {
        gs.error("ERROR=", e);
    }


})(request, response);

URL example:

https://<instance name>.service-now.com/api/<scripted API ID>/download_attachment?number=INC0000015&filename=hello_message.png

[Ovin Detree]

I am trying to have a direct URL to the file using the filename because we have a process in Java which needs to access the data in this excel file. I understand the sys_id will not be same everytime a new version is uploaded but we know that the filename will be same so we are trying to fetch it using the file name.

Thanks in advance.

Ovin

[Hitoshi Ozawa]

There's 2 choices, write a route in Java to call the ServiceNow APIs to find the sys_attachment sys_id or to write a Scripted REST API in ServiceNow. With Scripted REST API, Java app will only have to call once.

[Ovin Detree]

My only option is "write a route in Java to call the ServiceNow APIs to find the sys_attachment sys_id"

Is there a documentation or a sample code to find how to do this?

[Hitoshi Ozawa]

I'm in an emergency situation right now. I'll try to get my eclipse up when I get some time. Would need to call ServiceNow several times to get the file.