Network Error Logging

This is Express middleware to set the NEL HTTP response header. You can read more about it here.

To use:

constNEL=require('network-error-logging')// ...app.use(NEL({report_to: 'endpoint-1',// REQUIRED to register. OPTIONAL if intention is to remove a previous registration. defined in the Report-To headermax_age: 31_536_000,// REQUIRED. secondsinclude_subdomains: true,// OPTIONALsuccess_fraction: 0.5,// OPTIONAL. sampling ratefailure_fraction: 0.5,// OPTIONAL. sampling raterequest_headers: ["If-None-Match"],// OPTIONAL. request headers whose names and values are included in the network error reportsresponse_headers: ["ETag"]// OPTIONAL. response headers whose names and values are included in the network error reports}))

For further documentation on each field, see https://w3c.github.io/network-error-logging/#nel-response-header.

This header is best set with a previously defined Report-To group. This module is a great way to do that.

https://report-uri.com/ is a great reporting platform for monitoring CSP, NEL, etc. error logs.

License