func tripleToTriple(inFile io.Reader, outFile io.Writer, inFormat, outFormat rdf.Format, stream bool) int {
dec := rdf.NewTripleDecoder(inFile, inFormat)
// TODO set base to file name?
enc := rdf.NewTripleEncoder(outFile, outFormat)
i := 0
if stream {
for t, err := dec.Decode(); err != io.EOF; t, err = dec.Decode() {
if err != nil {
log.Fatal(err)
}
err = enc.Encode(t)
if err != nil {
log.Fatal(err)
}
i++
}
} else {
tr, err := dec.DecodeAll()
if err != nil {
log.Fatal(err)
}
err = enc.EncodeAll(tr)
if err != nil {
log.Fatal(err)
}
i = len(tr)
}
err := enc.Close()
if err != nil {
log.Fatal(err)
}
return i
}
// Construct performs a SPARQL HTTP request to the Repo, and returns the
// result triples.
func (r *Repo) Construct(q string) ([]rdf.Triple, error) {
form := url.Values{}
form.Set("query", q)
form.Set("format", "text/turtle")
b := form.Encode()
req, err := http.NewRequest(
"POST",
r.endpoint,
bytes.NewBufferString(b))
if err != nil {
return nil, err
}
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
req.Header.Set("Content-Length", strconv.Itoa(len(b)))
req.Header.Set("Accept", "text/turtle")
resp, err := r.client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
b, err := ioutil.ReadAll(resp.Body)
var msg string
if err != nil {
msg = "Failed to read response body"
} else {
if strings.TrimSpace(string(b)) != "" {
msg = "Response body: \n" + string(b)
}
}
return nil, fmt.Errorf("Construct: SPARQL request failed: %s. "+msg, resp.Status)
}
dec := rdf.NewTripleDecoder(resp.Body, rdf.Turtle)
return dec.DecodeAll()
}