84 lines
2.5 KiB
Go
84 lines
2.5 KiB
Go
// Copyright © 2016 Abcum Ltd
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package api
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import (
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"net/http"
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"strconv"
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"strings"
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"github.com/labstack/echo"
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)
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// CorsOpts defines options for the Head middleward
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type CorsOpts struct {
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AllowedMethods []string
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AllowedHeaders []string
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AccessControlMaxAge int
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}
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// Cors defines middleware for specifying CORS headers
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func Cors(opts *CorsOpts) echo.MiddlewareFunc {
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return func(h echo.HandlerFunc) echo.HandlerFunc {
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return func(c *echo.Context) error {
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origin := c.Request().Header.Get("Origin")
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if origin == "" {
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return h(c)
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}
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// Set default values for opts.AllowedMethods
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allowedMethods := opts.AllowedMethods
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if len(allowedMethods) == 0 {
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allowedMethods = []string{"GET", "PUT", "POST", "PATCH", "TRACE", "DELETE"}
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}
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// Set default values for opts.AllowedHeaders
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allowedHeaders := opts.AllowedHeaders
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if len(allowedHeaders) == 0 {
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allowedHeaders = []string{"Accept", "Content-Type", "Origin"}
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}
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// Set default values for opts.AccessControlMaxAge
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accessControlMaxAge := opts.AccessControlMaxAge
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if accessControlMaxAge == 0 {
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accessControlMaxAge = 3600
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}
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// Normalize AllowedMethods and make comma-separated-values
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normedMethods := []string{}
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for _, allowedMethod := range allowedMethods {
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normed := http.CanonicalHeaderKey(allowedMethod)
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normedMethods = append(normedMethods, normed)
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}
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// Normalize AllowedHeaders and make comma-separated-values
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normedHeaders := []string{}
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for _, allowedHeader := range allowedHeaders {
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normed := http.CanonicalHeaderKey(allowedHeader)
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normedHeaders = append(normedHeaders, normed)
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}
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c.Response().Header().Set("Access-Control-Allow-Methods", strings.Join(normedMethods, ","))
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c.Response().Header().Set("Access-Control-Allow-Headers", strings.Join(normedHeaders, ","))
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c.Response().Header().Set("Access-Control-Max-Age", strconv.Itoa(accessControlMaxAge))
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c.Response().Header().Set("Access-Control-Allow-Origin", origin)
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return h(c)
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}
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}
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}
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