Initial commit

.github/dependabot.yml

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+version: 2
+updates:
+  - package-ecosystem: "gomod"
+    directory: "/"
+    schedule:
+      interval: "daily"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"

.github/workflows/go.yml

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+name: Go
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.16
+
+    - name: Build
+      run: go build -v ./...
+
+    - name: Test
+      run: go test -v ./... -race -coverprofile=coverage.txt -covermode=atomic
+
+    - name: Upload coverage to Codecov
+      run: bash <(curl -s https://codecov.io/bash)
+
+  golangci:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v2
+        with:
+          version: latest

.gitignore

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+testdata/update-cache.json

.golangci.yaml

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+run:
+  skip-dirs-use-default: false
+
+linters:
+  enable: [ goheader ]
+
+linters-settings:
+  goheader:
+    template: |-
+      Copyright (c) {{ YEAR-RANGE }} {{ AUTHOR }}. All rights reserved.
+      Use of this source code is governed by a BSD-style
+      license that can be found in the LICENSE file.
+    values:
+      const:
+        AUTHOR: James Bowes

LICENSE

@@ -0,0 +1,29 @@
+BSD 3-Clause License
+
+Copyright (c) 2021, James Bowes
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

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+<!--
+  Attractive html formatting for rendering in github. sorry text editor
+  readers! Besides the header and section links, everything should be clean and
+  readable.
+-->
+<h1 align="center">whatsnew</h1>
+<p align="center"><i>Check for new github releases of your Golang application 🎊</i></p>
+
+<div align="center">
+  <a href="https://pkg.go.dev/github.com/jbowes/whatsnew"><img src="https://pkg.go.dev/badge/github.com/jbowes/whatsnew.svg" alt="Go Reference"></a>
+  <img alt="Alpha Quality" src="https://img.shields.io/badge/status-ALPHA-orange.svg" >
+  <a href="https://github.com/jbowes/whatsnew/releases/latest"><img alt="GitHub tag" src="https://img.shields.io/github/tag/jbowes/whatsnew.svg"></a>
+  <a href="https://github.com/jbowes/whatsnew/actions/workflows/go.yml"><img alt="Build Status" src="https://github.com/jbowes/whatsnew/actions/workflows/go.yml/badge.svg?branch=main"></a>
+  <a href="./LICENSE"><img alt="BSD license" src="https://img.shields.io/badge/license-BSD-blue.svg"></a>
+  <a href="https://codecov.io/gh/jbowes/whatsnew"><img alt="codecov" src="https://img.shields.io/codecov/c/github/jbowes/whatsnew.svg"></a>
+  <a href="https://goreportcard.com/report/github.com/jbowes/whatsnew"><img alt="Go Report Card" src="https://goreportcard.com/badge/github.com/jbowes/whatsnew"></a>
+</div><br /><br />
+
+---
+
+🚧 ___Disclaimer___: _`whatsnew` is alpha quality software. The API may change
+without warning between revisions._ 🚧
+
+[`whatsnew`][godoc] provides a simple way to check GitHub for new releases of
+your Go application. It saves results between runs, uses etags to speed up responses, and tries to minimize the overhead it adds to an otherwise fast
+application CLI run.
+
+If caching to disk, or reading from GitHub don't work for you, you can
+customize the behaviour.
+
+## Quick start
+
+```go
+import (
+  "context"
+  "github.com/jbowes/whatsnew"
+)
+
+func main() {
+	ctx := context.Background()
+
+	// Start a whatsnew Check
+	fut := whatsnew.Check(ctx, &whatsnew.Options{
+		Slug:    "you/your-app",
+		Cache:   "testdata/update-cache.json",
+		Version: "v0.0.1",
+	})
+
+	// Run your CLI code and whatnot
+
+	// Wait for the Check to complete, and show the results
+	if v, _ := fut.Get(); v != "" {
+		fmt.Printf("new release available: %s\n", v)
+	}
+}
+```
+
+For more usage and examples, see the [GoDoc Reference][godoc]
+
+## Alternatives
+
+`whatsnew` only **checks** for releases. If you're looking for a package that
+will let your application **update itself**, or you prefer packages that start
+with `go-`, consider one of these:
+- [go-github-selfupdate](https://github.com/rhysd/go-github-selfupdate)
+- [go-selfupdate](https://github.com/sanbornm/go-selfupdate)
+- [go-update](https://github.com/inconshreveable/go-update)
+
+## Contributing
+
+I would love your help!
+
+`whatsnew` is still a work in progress. You can help by:
+
+- Opening a pull request to resolve an [open issue][issues].
+- Adding a feature or enhancement of your own! If it might be big, please
+  [open an issue][enhancement] first so we can discuss it.
+- Improving this `README` or adding other documentation to `whatsnew`.
+- Letting [me] know if you're using `whatsnew`.
+
+[godoc]: https://pkg.go.dev/github.com/jbowes/whatsnew
+
+[issues]: ./issues
+[bug]: ./issues/new?labels=bug
+[enhancement]: ./issues/new?labels=enhancement
+
+[me]: https://twitter.com/jrbowes

examples_test.go

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+// Copyright (c) 2021 James Bowes. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package whatsnew_test
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/jbowes/whatsnew"
+	"github.com/jbowes/whatsnew/impl"
+)
+
+func Example() {
+	ctx := context.Background()
+	fut := whatsnew.Check(ctx, &whatsnew.Options{
+		Slug:    "you/your-app",
+		Cache:   "testdata/update-cache.json",
+		Version: "v0.0.1",
+	})
+
+	// Run your CLI code and whatnot
+
+	if v, _ := fut.Get(); v != "" {
+		fmt.Printf("new release available: %s\n", v)
+	}
+
+	// Output:
+	// new release available: v0.2.0
+}
+
+// This example test isn't really needed, but it keeps the file
+// from being an example program, so we can replace the http
+// transport etc.
+func Example_customFrequency() {
+	ctx := context.Background()
+	fut := whatsnew.Check(ctx, &whatsnew.Options{
+		Slug:      "you/your-app",
+		Cache:     "testdata/update-cache.json",
+		Version:   "0.0.1",
+		Frequency: 24 * time.Hour,
+	})
+
+	// Run your CLI code and whatnot
+
+	if v, _ := fut.Get(); v != "" {
+		fmt.Printf("new release available: %s\n", v)
+	}
+
+	// Output:
+	// new release available: 0.30.0
+}
+
+func init() {
+	ctx := context.Background()
+
+	// setup. write out a cache that will hit for one test and
+	// miss on the other
+	cache := impl.FileCacher{Path: "testdata/update-cache.json"}
+	_ = cache.Set(ctx, &impl.Info{
+		Version:   "v0.2.0",
+		CheckTime: time.Now().Add(-25 * time.Hour),
+		Etag:      "whatever",
+	})
+
+	// replace http default transport.
+	http.DefaultTransport = http.NewFileTransport(
+		http.Dir("testdata/example"),
+	)
+}

go.mod

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+module github.com/jbowes/whatsnew
+
+go 1.16
+
+require golang.org/x/mod v0.4.2

go.sum

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+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/mod v0.4.2 h1:Gz96sIWK3OalVv/I/qNygP42zyoKp3xptRVCWRFEBvo=
+golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

impl/file.go

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+// Copyright (c) 2021 James Bowes. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package impl
+
+import (
+	"context"
+	"encoding/json"
+	"os"
+)
+
+// FileCacher is the default Cacher used in whatsnew.
+type FileCacher struct {
+	Path string
+}
+
+// Get cached release Info.
+func (f *FileCacher) Get(context.Context) (*Info, error) {
+	r, err := os.Open(f.Path)
+	if err != nil {
+		return nil, err
+	}
+
+	var i Info
+	dec := json.NewDecoder(r)
+	err = dec.Decode(&i)
+	return &i, err
+}
+
+// Set cached release Info.
+func (f *FileCacher) Set(_ context.Context, i *Info) error {
+	w, err := os.Create(f.Path)
+	if err != nil {
+		return err
+	}
+
+	enc := json.NewEncoder(w)
+	enc.SetIndent("", "  ")
+
+	return enc.Encode(i)
+}

impl/github.go

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+// Copyright (c) 2021 James Bowes. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package impl
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"time"
+)
+
+// GitHubReleaser is the default Releaser used in whatsnew.
+type GitHubReleaser struct {
+	URL string // a complete URL to the releases API.
+}
+
+// Get a list of releases.
+func (g *GitHubReleaser) Get(ctx context.Context, etag string) ([]Release, string, error) {
+	req, err := http.NewRequest(http.MethodGet, g.URL, nil)
+	if err != nil {
+		return nil, "", err
+	}
+
+	req.Header.Set("Accept", "application/vnd.github.v3+json")
+	if etag != "" {
+		req.Header.Set("If-None-Match", etag)
+	}
+
+	// TODO: configurable timeout? relying on ctx doesn't seem like a great API
+	ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
+	defer cancel()
+
+	req = req.WithContext(ctx)
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+
+		return nil, "", err
+	}
+	defer resp.Body.Close()
+
+	if etag != "" && resp.StatusCode == http.StatusNotModified {
+		return nil, etag, nil // this will fall back to existing stuff.
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, "", fmt.Errorf("error getting updates: %s", resp.Status)
+	}
+
+	var rels []Release
+	dec := json.NewDecoder(resp.Body)
+	if err := dec.Decode(&rels); err != nil {
+		return nil, "", err
+	}
+
+	return rels, resp.Header.Get("Etag"), nil
+}