65 lines
1.5 KiB
Go
65 lines
1.5 KiB
Go
package main
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import (
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"errors"
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"io"
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)
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type HTTPCache struct {
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}
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// Based on http.MaxBytesReader
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// MaxBytesReader is similar to io.LimitReader but is intended for
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// limiting the size of incoming request bodies. In contrast to
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// io.LimitReader, MaxBytesReader's result is a ReadCloser, returns a
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// non-EOF error for a Read beyond the limit, and closes the
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// underlying reader when its Close method is called.
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//
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// MaxBytesReader prevents clients from accidentally or maliciously
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// sending a large request and wasting server resources.
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func MaxBytesReader(r io.ReadCloser, n int64) io.ReadCloser {
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if n < 0 { // Treat negative limits as equivalent to 0.
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n = 0
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}
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return &maxBytesReader{r: r, n: n}
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}
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type maxBytesReader struct {
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r io.ReadCloser // underlying reader
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n int64 // max bytes remaining
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err error // sticky error
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}
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func (l *maxBytesReader) Read(p []byte) (n int, err error) {
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if l.err != nil {
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return 0, l.err
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}
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if len(p) == 0 {
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return 0, nil
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}
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// If they asked for a 32KB byte read but only 5 bytes are
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// remaining, no need to read 32KB. 6 bytes will answer the
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// question of the whether we hit the limit or go past it.
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if int64(len(p)) > l.n+1 {
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p = p[:l.n+1]
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}
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n, err = l.r.Read(p)
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if int64(n) <= l.n {
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l.n -= int64(n)
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l.err = err
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return n, err
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}
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n = int(l.n)
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l.n = 0
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l.err = errors.New("http: response body too large")
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return n, l.err
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}
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func (l *maxBytesReader) Close() error {
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return l.r.Close()
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}
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