89 lines
3.4 KiB
Go
89 lines
3.4 KiB
Go
// Copyright 2019 The Go Cloud Development Kit Authors
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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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// https://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 docstore
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import (
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"context"
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"net/url"
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"gocloud.dev/internal/openurl"
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)
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// CollectionURLOpener opens a collection of documents based on a URL.
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// The opener must not modify the URL argument. It must be safe to call from
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// multiple goroutines.
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//
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// This interface is generally implemented by types in driver packages.
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type CollectionURLOpener interface {
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OpenCollectionURL(ctx context.Context, u *url.URL) (*Collection, error)
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}
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// URLMux is a URL opener multiplexer. It matches the scheme of the URLs against
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// a set of registered schemes and calls the opener that matches the URL's
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// scheme. See https://gocloud.dev/concepts/urls/ for more information.
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//
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// The zero value is a multiplexer with no registered scheme.
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type URLMux struct {
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schemes openurl.SchemeMap
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}
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// CollectionSchemes returns a sorted slice of the registered Collection schemes.
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func (mux *URLMux) CollectionSchemes() []string { return mux.schemes.Schemes() }
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// ValidCollectionScheme returns true iff scheme has been registered for Collections.
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func (mux *URLMux) ValidCollectionScheme(scheme string) bool { return mux.schemes.ValidScheme(scheme) }
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// RegisterCollection registers the opener with the given scheme. If an opener
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// already exists for the scheme, RegisterCollection panics.
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func (mux *URLMux) RegisterCollection(scheme string, opener CollectionURLOpener) {
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mux.schemes.Register("docstore", "Collection", scheme, opener)
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}
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// OpenCollection calls OpenCollectionURL with the URL parsed from urlstr.
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// OpenCollection is safe to call from multiple goroutines.
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func (mux *URLMux) OpenCollection(ctx context.Context, urlstr string) (*Collection, error) {
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opener, u, err := mux.schemes.FromString("Collection", urlstr)
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if err != nil {
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return nil, err
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}
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return opener.(CollectionURLOpener).OpenCollectionURL(ctx, u)
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}
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// OpenCollectionURL dispatches the URL to the opener that is registered with
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// the URL's scheme. OpenCollectionURL is safe to call from multiple goroutines.
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func (mux *URLMux) OpenCollectionURL(ctx context.Context, u *url.URL) (*Collection, error) {
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opener, err := mux.schemes.FromURL("Collection", u)
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if err != nil {
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return nil, err
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}
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return opener.(CollectionURLOpener).OpenCollectionURL(ctx, u)
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}
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var defaultURLMux = new(URLMux)
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// DefaultURLMux returns the URLMux used by OpenCollection.
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//
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// Driver packages can use this to register their CollectionURLOpener on the mux.
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func DefaultURLMux() *URLMux {
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return defaultURLMux
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}
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// OpenCollection opens the collection identified by the URL given.
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// See the URLOpener documentation in driver subpackages for details
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// on supported URL formats, and https://gocloud.dev/concepts/urls/ for more
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// information.
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func OpenCollection(ctx context.Context, urlstr string) (*Collection, error) {
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return defaultURLMux.OpenCollection(ctx, urlstr)
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}
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