The http.cors.allow-methods setting in Elasticsearch controls which HTTP methods are allowed for Cross-Origin Resource Sharing (CORS) requests. It specifies the HTTP methods that can be used when accessing Elasticsearch from a different domain.
Description
- Default value:
OPTIONS, HEAD, GET, POST, PUT, DELETE - Possible values: Any combination of HTTP methods, separated by commas
- Recommendations: Only allow the methods necessary for your application to function
This setting is part of Elasticsearch's CORS configuration. It works in conjunction with other CORS-related settings to define how Elasticsearch responds to cross-origin requests. When configuring this setting, consider the security implications and only allow the methods that are absolutely necessary for your use case.
Example
To change the http.cors.allow-methods setting using the cluster settings API:
PUT /_cluster/settings
{
"persistent": {
"http.cors.allow-methods": "GET, POST, OPTIONS"
}
}
In this example, we're restricting the allowed methods to GET, POST, and OPTIONS. This might be appropriate for an application that only needs to read and write data, without needing to perform deletions or updates.
Common Issues
- Overly permissive settings: Allowing all methods when only a subset is needed can pose security risks.
- Forgetting to include OPTIONS: The OPTIONS method is required for CORS preflight requests.
- Misconfiguration leading to CORS errors: If methods used by your application are not included, it may result in CORS errors.
Do's and Don'ts
Do's:
- Only allow the methods your application actually needs
- Always include OPTIONS if you're using CORS
- Regularly review and update your CORS settings
Don'ts:
- Don't allow all methods by default
- Don't forget to update this setting when your application's requirements change
- Don't ignore CORS-related errors; they often indicate a misconfiguration
Frequently Asked Questions
Q: Why is the OPTIONS method important for CORS?
A: The OPTIONS method is used for CORS preflight requests. Browsers send these requests to check if the actual request is safe to send. Without allowing OPTIONS, CORS requests will fail.
Q: Can I use wildcards in the http.cors.allow-methods setting?
A: No, you need to explicitly list each allowed method. Wildcards are not supported for this setting.
Q: How does this setting interact with http.cors.enabled?
A: The http.cors.enabled setting must be set to true for any CORS settings, including http.cors.allow-methods, to take effect.
Q: Is it safe to allow all methods (GET, POST, PUT, DELETE, etc.)?
A: While it's possible, it's generally not recommended from a security standpoint. It's better to only allow the methods your application actually needs.
Q: How can I troubleshoot CORS issues related to allowed methods?
A: Check your browser's developer console for CORS-related errors. Ensure that the methods your application is using are included in the http.cors.allow-methods setting. Also, verify that CORS is enabled and other CORS-related settings are correctly configured.
