|
| 1 | +//go:build !lambdahttpadapter.partial || (lambdahttpadapter.partial && lambdahttpadapter.alb) |
| 2 | + |
| 3 | +package handler |
| 4 | + |
| 5 | +import ( |
| 6 | + "bytes" |
| 7 | + "context" |
| 8 | + "encoding/base64" |
| 9 | + "github.com/aws/aws-lambda-go/events" |
| 10 | + "io" |
| 11 | + "net/http" |
| 12 | + "net/url" |
| 13 | + "strconv" |
| 14 | + "strings" |
| 15 | + "unicode/utf8" |
| 16 | +) |
| 17 | + |
| 18 | +func convertALBRequest(ctx context.Context, event events.ALBTargetGroupRequest) (*http.Request, error) { |
| 19 | + q := make(url.Values) |
| 20 | + |
| 21 | + if len(event.MultiValueQueryStringParameters) > 0 { |
| 22 | + for k, values := range event.MultiValueQueryStringParameters { |
| 23 | + for _, v := range values { |
| 24 | + q.Add(k, v) |
| 25 | + } |
| 26 | + } |
| 27 | + } else if len(event.QueryStringParameters) > 0 { |
| 28 | + for k, v := range event.QueryStringParameters { |
| 29 | + q.Add(k, v) |
| 30 | + } |
| 31 | + } |
| 32 | + |
| 33 | + headers := make(http.Header) |
| 34 | + if event.Headers != nil { |
| 35 | + for k, v := range event.Headers { |
| 36 | + headers.Add(k, v) |
| 37 | + } |
| 38 | + } |
| 39 | + |
| 40 | + if event.MultiValueHeaders != nil { |
| 41 | + for k, values := range event.MultiValueHeaders { |
| 42 | + for _, v := range values { |
| 43 | + headers.Add(k, v) |
| 44 | + } |
| 45 | + } |
| 46 | + } |
| 47 | + |
| 48 | + host := headers.Get("X-Forwarded-Host") |
| 49 | + if host == "" { |
| 50 | + host = headers.Get("Host") |
| 51 | + if host == "" { |
| 52 | + host = "127.0.0.1" |
| 53 | + } |
| 54 | + } |
| 55 | + |
| 56 | + sourceIp := headers.Get("X-Forwarded-For") |
| 57 | + if sourceIp == "" { |
| 58 | + sourceIp = "127.0.0.1" |
| 59 | + } |
| 60 | + |
| 61 | + proto := headers.Get("X-Forwarded-Proto") |
| 62 | + if proto == "" { |
| 63 | + proto = "http" |
| 64 | + } |
| 65 | + |
| 66 | + rUrl := buildFullRequestURLWithProto(proto, host, event.Path, "", q.Encode()) |
| 67 | + req, err := http.NewRequestWithContext(ctx, event.HTTPMethod, rUrl, getBody(event.Body, event.IsBase64Encoded)) |
| 68 | + if err != nil { |
| 69 | + return nil, err |
| 70 | + } |
| 71 | + |
| 72 | + req.Header = headers |
| 73 | + req.RemoteAddr = buildRemoteAddr(sourceIp) |
| 74 | + req.RequestURI = req.URL.RequestURI() |
| 75 | + |
| 76 | + return req, nil |
| 77 | +} |
| 78 | + |
| 79 | +type albResponseWriter struct { |
| 80 | + multiValueHeaders bool |
| 81 | + headersWritten bool |
| 82 | + contentTypeSet bool |
| 83 | + contentLengthSet bool |
| 84 | + headers http.Header |
| 85 | + body bytes.Buffer |
| 86 | + res events.ALBTargetGroupResponse |
| 87 | +} |
| 88 | + |
| 89 | +func (w *albResponseWriter) Header() http.Header { |
| 90 | + return w.headers |
| 91 | +} |
| 92 | + |
| 93 | +func (w *albResponseWriter) Write(p []byte) (int, error) { |
| 94 | + w.WriteHeader(http.StatusOK) |
| 95 | + return w.body.Write(p) |
| 96 | +} |
| 97 | + |
| 98 | +func (w *albResponseWriter) WriteHeader(statusCode int) { |
| 99 | + if !w.headersWritten { |
| 100 | + w.headersWritten = true |
| 101 | + w.res.StatusCode = statusCode |
| 102 | + |
| 103 | + for k, values := range w.headers { |
| 104 | + if w.multiValueHeaders { |
| 105 | + w.res.MultiValueHeaders[k] = values |
| 106 | + } else { |
| 107 | + w.res.Headers[k] = strings.Join(values, ",") |
| 108 | + } |
| 109 | + } |
| 110 | + } |
| 111 | +} |
| 112 | + |
| 113 | +func handleALB(multiValueHeaders bool) func(ctx context.Context, event events.ALBTargetGroupRequest, adapter AdapterFunc) (events.ALBTargetGroupResponse, error) { |
| 114 | + return func(ctx context.Context, event events.ALBTargetGroupRequest, adapter AdapterFunc) (events.ALBTargetGroupResponse, error) { |
| 115 | + req, err := convertALBRequest(ctx, event) |
| 116 | + if err != nil { |
| 117 | + var def events.ALBTargetGroupResponse |
| 118 | + return def, err |
| 119 | + } |
| 120 | + |
| 121 | + w := albResponseWriter{ |
| 122 | + multiValueHeaders: multiValueHeaders, |
| 123 | + headers: make(http.Header), |
| 124 | + res: events.ALBTargetGroupResponse{}, |
| 125 | + } |
| 126 | + |
| 127 | + if multiValueHeaders { |
| 128 | + w.res.MultiValueHeaders = make(map[string][]string) |
| 129 | + } else { |
| 130 | + w.res.Headers = make(map[string]string) |
| 131 | + } |
| 132 | + |
| 133 | + if err = adapter(ctx, req, &w); err != nil { |
| 134 | + var def events.ALBTargetGroupResponse |
| 135 | + return def, err |
| 136 | + } |
| 137 | + |
| 138 | + b, err := io.ReadAll(&w.body) |
| 139 | + if err != nil { |
| 140 | + var def events.ALBTargetGroupResponse |
| 141 | + return def, err |
| 142 | + } |
| 143 | + |
| 144 | + if !w.contentTypeSet { |
| 145 | + w.res.Headers["Content-Type"] = http.DetectContentType(b) |
| 146 | + } |
| 147 | + |
| 148 | + if !w.contentLengthSet { |
| 149 | + w.res.Headers["Content-Length"] = strconv.Itoa(len(b)) |
| 150 | + } |
| 151 | + |
| 152 | + if utf8.Valid(b) { |
| 153 | + w.res.Body = string(b) |
| 154 | + } else { |
| 155 | + w.res.IsBase64Encoded = true |
| 156 | + w.res.Body = base64.StdEncoding.EncodeToString(b) |
| 157 | + } |
| 158 | + |
| 159 | + return w.res, nil |
| 160 | + } |
| 161 | +} |
| 162 | + |
| 163 | +func NewALBHandler(adapter AdapterFunc, multiValueHeaders bool) func(context.Context, events.ALBTargetGroupRequest) (events.ALBTargetGroupResponse, error) { |
| 164 | + return NewHandler(handleALB(multiValueHeaders), adapter) |
| 165 | +} |
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