go-gemini/response.go

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package gemini
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import (
"bufio"
"bytes"
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"crypto/tls"
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"io"
"io/ioutil"
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"strconv"
)
// Response is a Gemini response.
type Response struct {
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// Status contains the response status code.
Status Status
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// Meta contains more information related to the response status.
// For successful responses, Meta should contain the mimetype of the response.
// For failure responses, Meta should contain a short description of the failure.
// Meta should not be longer than 1024 bytes.
Meta string
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// Body contains the response body for successful responses.
// Body is guaranteed to be non-nil.
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Body io.ReadCloser
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// Request is the request that was sent to obtain this response.
Request *Request
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// TLS contains information about the TLS connection on which the response
// was received.
TLS tls.ConnectionState
}
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// read reads a Gemini response from the provided io.ReadCloser.
func (resp *Response) read(rc io.ReadCloser) error {
br := bufio.NewReader(rc)
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// Read the status
statusB := make([]byte, 2)
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if _, err := br.Read(statusB); err != nil {
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return err
}
status, err := strconv.Atoi(string(statusB))
if err != nil {
return err
}
resp.Status = Status(status)
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// Disregard invalid status codes
const minStatus, maxStatus = 1, 6
statusClass := resp.Status.Class()
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if statusClass < minStatus || statusClass > maxStatus {
return ErrInvalidResponse
}
// Read one space
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if b, err := br.ReadByte(); err != nil {
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return err
} else if b != ' ' {
return ErrInvalidResponse
}
// Read the meta
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meta, err := br.ReadString('\r')
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if err != nil {
return err
}
// Trim carriage return
meta = meta[:len(meta)-1]
// Ensure meta is less than or equal to 1024 bytes
if len(meta) > 1024 {
return ErrInvalidResponse
}
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// Default mime type of text/gemini; charset=utf-8
if statusClass == StatusClassSuccess && meta == "" {
meta = "text/gemini; charset=utf-8"
}
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resp.Meta = meta
// Read terminating newline
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if b, err := br.ReadByte(); err != nil {
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return err
} else if b != '\n' {
return ErrInvalidResponse
}
if resp.Status.Class() == StatusClassSuccess {
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resp.Body = newReadCloserBody(br, rc)
} else {
resp.Body = ioutil.NopCloser(bytes.NewReader([]byte{}))
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}
return nil
}
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type readCloserBody struct {
br *bufio.Reader // used until empty
io.ReadCloser
}
func newReadCloserBody(br *bufio.Reader, rc io.ReadCloser) io.ReadCloser {
body := &readCloserBody{ReadCloser: rc}
if br.Buffered() != 0 {
body.br = br
}
return body
}
func (b *readCloserBody) Read(p []byte) (n int, err error) {
if b.br != nil {
if n := b.br.Buffered(); len(p) > n {
p = p[:n]
}
n, err = b.br.Read(p)
if b.br.Buffered() == 0 {
b.br = nil
}
return n, err
}
return b.ReadCloser.Read(p)
}