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Resume interrupted connections. This makes the client.Client an interface as a test seam (so we can easily mock it). Additionally this now allows pget to resume downloads if a connection is interruped before the chunk is delivered. This should reduce the potential for unexpectedEOF errors being bubbled up to the end user.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,11 +1,88 @@ | ||
| package download | ||
|
|
||
| import ( | ||
| "errors" | ||
| "fmt" | ||
| "io" | ||
| "net/http" | ||
| "regexp" | ||
| "strconv" | ||
| "strings" | ||
|
|
||
| "github.com/dustin/go-humanize" | ||
|
|
||
| "github.com/replicate/pget/pkg/client" | ||
| ) | ||
|
|
||
| const defaultChunkSize = 125 * humanize.MiByte | ||
|
|
||
| var contentRangeRegexp = regexp.MustCompile(`^bytes .*/([0-9]+)$`) | ||
| var ( | ||
| contentRangeRegexp = regexp.MustCompile(`^bytes .*/([0-9]+)$`) | ||
|
|
||
| errMalformedRangeHeader = errors.New("malformed range header") | ||
| errMissingRangeHeader = errors.New("missing range header") | ||
| errInvalidContentRange = errors.New("invalid content range") | ||
| ) | ||
|
|
||
| func resumeDownload(req *http.Request, buffer []byte, client client.HTTPClient, bytesReceived int64) (*http.Response, error) { | ||
| var startByte int | ||
| for { | ||
| var n int | ||
| if err := updateRangeRequestHeader(req, bytesReceived); err != nil { | ||
| return nil, err | ||
| } | ||
| resp, err := client.Do(req) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| defer resp.Body.Close() | ||
| if resp.StatusCode != http.StatusPartialContent { | ||
| return nil, fmt.Errorf("expected status code %d, got %d", http.StatusPartialContent, resp.StatusCode) | ||
| } | ||
| n, err = io.ReadFull(resp.Body, buffer[startByte:]) | ||
| if err == io.ErrUnexpectedEOF { | ||
| startByte = n | ||
| continue | ||
| } | ||
| return nil, err | ||
|
|
||
| } | ||
| } | ||
|
|
||
| func updateRangeRequestHeader(req *http.Request, receivedBytes int64) error { | ||
| rangeHeader := req.Header.Get("Range") | ||
| if rangeHeader == "" { | ||
| return errMissingRangeHeader | ||
| } | ||
|
|
||
| // Expected format: "bytes=start-end" | ||
| if !strings.HasPrefix(rangeHeader, "bytes=") { | ||
| return fmt.Errorf("%w: %s", errMalformedRangeHeader, rangeHeader) | ||
| } | ||
|
|
||
| rangeValues := strings.TrimPrefix(rangeHeader, "bytes=") | ||
| parts := strings.Split(rangeValues, "-") | ||
| if len(parts) != 2 { | ||
| return fmt.Errorf("%w: %s", errMalformedRangeHeader, rangeHeader) | ||
| } | ||
|
|
||
| start, err := strconv.ParseInt(parts[0], 10, 64) | ||
| if err != nil { | ||
| return fmt.Errorf("%w: %s", errMalformedRangeHeader, rangeHeader) | ||
| } | ||
|
|
||
| end, err := strconv.ParseInt(parts[1], 10, 64) | ||
| if err != nil { | ||
| return fmt.Errorf("%w: %s", errMalformedRangeHeader, rangeHeader) | ||
| } | ||
|
|
||
| start = start + receivedBytes | ||
| if start > end { | ||
| return fmt.Errorf("%w: %s", errInvalidContentRange, rangeHeader) | ||
| } | ||
|
|
||
| newRangeHeader := fmt.Sprintf("bytes=%d-%d", start, end) | ||
| req.Header.Set("Range", newRangeHeader) | ||
|
|
||
| return nil | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,189 @@ | ||
| package download | ||
|
|
||
| import ( | ||
| "bytes" | ||
| "errors" | ||
| "io" | ||
| "net/http" | ||
| "net/http/httptest" | ||
| "testing" | ||
| "time" | ||
|
|
||
| "github.com/stretchr/testify/assert" | ||
| "github.com/stretchr/testify/require" | ||
| "go.uber.org/atomic" | ||
| ) | ||
|
|
||
| type mockHTTPClient struct { | ||
| doFunc func(req *http.Request) (*http.Response, error) | ||
| callCount atomic.Int32 | ||
| } | ||
|
|
||
| func (m *mockHTTPClient) Do(req *http.Request) (*http.Response, error) { | ||
| m.callCount.Add(1) | ||
| return m.doFunc(req) | ||
| } | ||
|
|
||
| func TestResumeDownload(t *testing.T) { | ||
| tests := []struct { | ||
| name string | ||
| serverContent string | ||
| bytesReceived int64 | ||
| initialRange string | ||
| expectedError error | ||
| expectedOutput []byte | ||
| expectedCalls int32 | ||
| }{ | ||
| { | ||
| name: "successful download", | ||
| serverContent: "Hello, world!", | ||
| bytesReceived: 0, | ||
| initialRange: "bytes=0-12", | ||
| expectedError: nil, | ||
| expectedOutput: []byte("Hello, world!"), | ||
| expectedCalls: 1, | ||
| }, | ||
| { | ||
| name: "partial download", | ||
| serverContent: "Hello, world!", | ||
| bytesReceived: 3, | ||
| initialRange: "bytes=7-12", | ||
| expectedError: nil, | ||
| expectedOutput: []byte("world!"), | ||
| expectedCalls: 1, | ||
| }, | ||
| { | ||
| name: "network error", | ||
| serverContent: "Hello, world!", | ||
| bytesReceived: 0, | ||
| initialRange: "bytes=0-12", | ||
| expectedError: errors.New("network error"), | ||
| expectedOutput: nil, | ||
| expectedCalls: 1, | ||
| }, | ||
| { | ||
| name: "multi-pass download", | ||
| serverContent: "12345678901234567890", | ||
| bytesReceived: 3, | ||
| initialRange: "bytes=10-19", | ||
| expectedError: nil, | ||
| expectedOutput: []byte("0123456789"), | ||
| expectedCalls: 2, | ||
| }, | ||
| } | ||
|
|
||
| for _, tt := range tests { | ||
| t.Run(tt.name, func(t *testing.T) { | ||
| server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { | ||
| http.ServeContent(w, r, "", time.Time{}, bytes.NewReader([]byte(tt.serverContent))) | ||
| })) | ||
| defer server.Close() | ||
|
|
||
| req, err := http.NewRequest("GET", server.URL, nil) | ||
| assert.NoError(t, err) | ||
|
|
||
| // Set the initial Range header from the test case | ||
| req.Header.Set("Range", tt.initialRange) | ||
|
|
||
| buffer := make([]byte, len(tt.expectedOutput)) | ||
| copy(buffer, tt.expectedOutput[:tt.bytesReceived]) | ||
| mockClient := &mockHTTPClient{ | ||
| doFunc: func(req *http.Request) (*http.Response, error) { | ||
| if tt.name == "network error" { | ||
| return nil, errors.New("network error") | ||
| } | ||
| if tt.name == "multi-pass download" { | ||
| switch req.Header.Get("Range") { | ||
| case "bytes=16-19": | ||
| return &http.Response{ | ||
| StatusCode: http.StatusPartialContent, | ||
| Body: io.NopCloser(bytes.NewReader([]byte("56789"))), | ||
| Header: http.Header{"Content-Range": []string{"bytes 15-20/21"}}, | ||
| }, nil | ||
| case "bytes=13-19": | ||
| return &http.Response{ | ||
| StatusCode: http.StatusPartialContent, | ||
| Body: io.NopCloser(bytes.NewReader([]byte("34"))), | ||
| Header: http.Header{"Content-Range": []string{"bytes 13-20/21"}}, | ||
| }, nil | ||
| } | ||
| } | ||
| return http.DefaultClient.Do(req) | ||
| }, | ||
| } | ||
|
|
||
| _, err = resumeDownload(req, buffer[tt.bytesReceived:], mockClient, tt.bytesReceived) | ||
| if tt.expectedError != nil { | ||
| assert.Error(t, err) | ||
| assert.Equal(t, tt.expectedError.Error(), err.Error()) | ||
| } else { | ||
| assert.NoError(t, err) | ||
| assert.Equal(t, tt.expectedOutput, buffer[:len(tt.expectedOutput)]) | ||
| } | ||
| assert.Equal(t, tt.expectedCalls, mockClient.callCount.Load(), "Unexpected number of HTTP client calls") | ||
| }) | ||
| } | ||
| } | ||
|
|
||
| func TestUpdateRangeRequestHeader(t *testing.T) { | ||
| tests := []struct { | ||
| name string | ||
| initialRange string | ||
| receivedBytes int64 | ||
| expectedRange string | ||
| expectedError error | ||
| }{ | ||
| { | ||
| name: "valid range header", | ||
| initialRange: "bytes=0-10", | ||
| receivedBytes: 5, | ||
| expectedRange: "bytes=5-10", | ||
| expectedError: nil, | ||
| }, | ||
| { | ||
| name: "non-zero initial range", | ||
| initialRange: "bytes=7-12", | ||
| receivedBytes: 3, | ||
| expectedRange: "bytes=10-12", | ||
| expectedError: nil, | ||
| }, | ||
| { | ||
| name: "missing range header", | ||
| initialRange: "", | ||
| receivedBytes: 5, | ||
| expectedRange: "", | ||
| expectedError: errMissingRangeHeader, | ||
| }, | ||
| { | ||
| name: "malformed range header", | ||
| initialRange: "bytes=malformed", | ||
| receivedBytes: 5, | ||
| expectedRange: "", | ||
| expectedError: errMalformedRangeHeader, | ||
| }, | ||
| { | ||
| name: "receivedBytes exceeds range", | ||
| initialRange: "bytes=0-10", | ||
| receivedBytes: 15, | ||
| expectedRange: "", | ||
| expectedError: errInvalidContentRange, | ||
| }, | ||
| } | ||
|
|
||
| for _, tt := range tests { | ||
| t.Run(tt.name, func(t *testing.T) { | ||
| req, err := http.NewRequest("GET", "http://example.com", nil) | ||
| assert.NoError(t, err) | ||
| req.Header.Set("Range", tt.initialRange) | ||
|
|
||
| err = updateRangeRequestHeader(req, tt.receivedBytes) | ||
| if tt.expectedError != nil { | ||
| require.Error(t, err) | ||
| assert.ErrorIs(t, err, tt.expectedError) | ||
| } else { | ||
| assert.NoError(t, err) | ||
| assert.Equal(t, tt.expectedRange, req.Header.Get("Range")) | ||
| } | ||
| }) | ||
| } | ||
| } |
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