package httprs import ( "fmt" "io" "io/ioutil" "net/http" "net/http/httptest" "os" "path/filepath" "testing" "time" . "github.com/smartystreets/goconvey/convey" ) type fakeResponseWriter struct { code int h http.Header tmp *os.File } func (f *fakeResponseWriter) Header() http.Header { return f.h } func (f *fakeResponseWriter) Write(b []byte) (int, error) { return f.tmp.Write(b) } func (f *fakeResponseWriter) Close(b []byte) error { return f.tmp.Close() } func (f *fakeResponseWriter) WriteHeader(code int) { f.code = code } func (f *fakeResponseWriter) Response() *http.Response { f.tmp.Seek(0, io.SeekStart) return &http.Response{Body: f.tmp, StatusCode: f.code, Header: f.h} } type fakeRoundTripper struct { src *os.File downgradeZeroToNoRange bool } func (f *fakeRoundTripper) RoundTrip(r *http.Request) (*http.Response, error) { fw := &fakeResponseWriter{h: http.Header{}} var err error fw.tmp, err = ioutil.TempFile(os.TempDir(), "httprs") if err != nil { return nil, err } if f.downgradeZeroToNoRange { // There are implementations that downgrades bytes=0- to a normal un-ranged GET if r.Header.Get("Range") == "bytes=0-" { r.Header.Del("Range") } } http.ServeContent(fw, r, "temp.txt", time.Now(), f.src) return fw.Response(), nil } const SZ = 4096 const ( downgradeZeroToNoRange = 1 << iota sendAcceptRanges ) type RSFactory func() *HttpReadSeeker func newRSFactory(flags int) RSFactory { return func() *HttpReadSeeker { tmp, err := ioutil.TempFile(os.TempDir(), "httprs") if err != nil { return nil } for i := 0; i < SZ; i++ { tmp.WriteString(fmt.Sprintf("%04d", i)) } req, err := http.NewRequest("GET", "http://www.example.com", nil) if err != nil { return nil } res := &http.Response{ Request: req, ContentLength: SZ * 4, } if flags&sendAcceptRanges > 0 { res.Header = http.Header{"Accept-Ranges": []string{"bytes"}} } downgradeZeroToNoRange := (flags & downgradeZeroToNoRange) > 0 return NewHttpReadSeeker(res, &http.Client{Transport: &fakeRoundTripper{src: tmp, downgradeZeroToNoRange: downgradeZeroToNoRange}}) } } func TestHttpWebServer(t *testing.T) { Convey("Scenario: testing WebServer", t, func() { dir, err := ioutil.TempDir("", "webserver") So(err, ShouldBeNil) defer os.RemoveAll(dir) err = ioutil.WriteFile(filepath.Join(dir, "file"), make([]byte, 10000), 0755) So(err, ShouldBeNil) server := httptest.NewServer(http.FileServer(http.Dir(dir))) Convey("When requesting /file", func() { res, err := http.Get(server.URL + "/file") So(err, ShouldBeNil) stream := NewHttpReadSeeker(res) So(stream, ShouldNotBeNil) Convey("Can read 100 bytes from start of file", func() { n, err := stream.Read(make([]byte, 100)) So(err, ShouldBeNil) So(n, ShouldEqual, 100) Convey("When seeking 4KiB forward", func() { pos, err := stream.Seek(4096, io.SeekCurrent) So(err, ShouldBeNil) So(pos, ShouldEqual, 4096+100) Convey("Can read 100 bytes", func() { n, err := stream.Read(make([]byte, 100)) So(err, ShouldBeNil) So(n, ShouldEqual, 100) }) }) }) }) }) } func TestHttpReaderSeeker(t *testing.T) { tests := []struct { name string newRS func() *HttpReadSeeker }{ {name: "with no flags", newRS: newRSFactory(0)}, {name: "with only Accept-Ranges", newRS: newRSFactory(sendAcceptRanges)}, {name: "downgrade 0-range to no range", newRS: newRSFactory(downgradeZeroToNoRange)}, {name: "downgrade 0-range with Accept-Ranges", newRS: newRSFactory(downgradeZeroToNoRange | sendAcceptRanges)}, } for _, test := range tests { t.Run(test.name, func(t *testing.T) { testHttpReaderSeeker(t, test.newRS) }) } } func testHttpReaderSeeker(t *testing.T, newRS RSFactory) { Convey("Scenario: testing HttpReaderSeeker", t, func() { Convey("Read should start at the beginning", func() { r := newRS() So(r, ShouldNotBeNil) defer r.Close() buf := make([]byte, 4) n, err := io.ReadFull(r, buf) So(n, ShouldEqual, 4) So(err, ShouldBeNil) So(string(buf), ShouldEqual, "0000") }) Convey("Seek w SEEK_SET should seek to right offset", func() { r := newRS() So(r, ShouldNotBeNil) defer r.Close() s, err := r.Seek(4*64, io.SeekStart) So(s, ShouldEqual, 4*64) So(err, ShouldBeNil) buf := make([]byte, 4) n, err := io.ReadFull(r, buf) So(n, ShouldEqual, 4) So(err, ShouldBeNil) So(string(buf), ShouldEqual, "0064") }) Convey("Read + Seek w SEEK_CUR should seek to right offset", func() { r := newRS() So(r, ShouldNotBeNil) defer r.Close() buf := make([]byte, 4) io.ReadFull(r, buf) s, err := r.Seek(4*64, os.SEEK_CUR) So(s, ShouldEqual, 4*64+4) So(err, ShouldBeNil) n, err := io.ReadFull(r, buf) So(n, ShouldEqual, 4) So(err, ShouldBeNil) So(string(buf), ShouldEqual, "0065") }) Convey("Seek w SEEK_END should seek to right offset", func() { r := newRS() So(r, ShouldNotBeNil) defer r.Close() buf := make([]byte, 4) io.ReadFull(r, buf) s, err := r.Seek(4, os.SEEK_END) So(s, ShouldEqual, SZ*4-4) So(err, ShouldBeNil) n, err := io.ReadFull(r, buf) So(n, ShouldEqual, 4) So(err, ShouldBeNil) So(string(buf), ShouldEqual, fmt.Sprintf("%04d", SZ-1)) }) Convey("Short seek should consume existing request", func() { r := newRS() So(r, ShouldNotBeNil) defer r.Close() buf := make([]byte, 4) So(r.Requests, ShouldEqual, 0) io.ReadFull(r, buf) So(r.Requests, ShouldEqual, 1) s, err := r.Seek(shortSeekBytes, os.SEEK_CUR) So(r.Requests, ShouldEqual, 1) So(s, ShouldEqual, shortSeekBytes+4) So(err, ShouldBeNil) n, err := io.ReadFull(r, buf) So(n, ShouldEqual, 4) So(err, ShouldBeNil) So(string(buf), ShouldEqual, "0257") So(r.Requests, ShouldEqual, 1) }) Convey("Long seek should do a new request", func() { r := newRS() So(r, ShouldNotBeNil) defer r.Close() buf := make([]byte, 4) So(r.Requests, ShouldEqual, 0) io.ReadFull(r, buf) So(r.Requests, ShouldEqual, 1) s, err := r.Seek(shortSeekBytes+1, os.SEEK_CUR) So(r.Requests, ShouldEqual, 1) So(s, ShouldEqual, shortSeekBytes+4+1) So(err, ShouldBeNil) n, err := io.ReadFull(r, buf) So(n, ShouldEqual, 4) So(err, ShouldBeNil) So(string(buf), ShouldEqual, "2570") So(r.Requests, ShouldEqual, 2) }) }) }