before_fetch

before_fetch(request, ctx) runs on the executor thread before every HTTP request. Modify the URL, add headers, or return nil to skip this run entirely.

Signature

function before_fetch(request, ctx) -> table | nil

Parameters

Field	Type	Mutable	Description
request.url	string	yes	Target URL
request.method	string	yes	HTTP method (GET, HEAD, DELETE, etc.)
request.headers	table	yes	HTTP headers (string→string)
request.timeout	number / nil	yes	Per-request timeout in seconds (default: 30)
request.proxy	string / nil	yes	Per-request proxy URL (overrides job proxy config)
request.max_body_size	number / nil	yes	Max response body in MB (integer, default: 10)

Returns

Return	Effect
request table	Continue with modified request
nil / false	Skip this entire run

Example

function before_fetch(request, ctx)
    request.headers["Authorization"] = "Bearer my-token"
    return request
end

function before_fetch(request, ctx)
    page = page or 1
    request.url = request.url .. "?page=" .. page
    page = page + 1
    if page > 10 then page = 1 end
    return request
end

See Also

• override_fetch - Replace the entire fetch with custom logic
• after_fetch - Process the response after fetching