BearerAuth, BasicAuth and DefaultHeaders mutated the caller's request, which violates the RoundTripper contract and risks races on shared/retried requests; clone before writing headers (matching RequestID). Validate the incoming X-Request-Id (length and character set) before propagating it to logs and the response header, preventing log forging and header splitting from a client-controlled value.
37 lines
1.0 KiB
Go
37 lines
1.0 KiB
Go
package middleware
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import "net/http"
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// DefaultHeaders returns a middleware that adds the given headers to every
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// outgoing request. Existing headers on the request are not overwritten.
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func DefaultHeaders(headers http.Header) Middleware {
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return func(next http.RoundTripper) http.RoundTripper {
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return RoundTripperFunc(func(req *http.Request) (*http.Response, error) {
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// Clone lazily on the first header we actually add, so that
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// RoundTrippers never mutate the caller's request.
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cloned := false
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for key, values := range headers {
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if req.Header.Get(key) != "" {
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continue
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}
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if !cloned {
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req = req.Clone(req.Context())
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cloned = true
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}
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for _, v := range values {
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req.Header.Add(key, v)
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}
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}
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return next.RoundTrip(req)
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})
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}
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}
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// UserAgent returns a middleware that sets the User-Agent header on every
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// outgoing request, unless one is already present.
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func UserAgent(ua string) Middleware {
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return DefaultHeaders(http.Header{
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"User-Agent": {ua},
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})
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}
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