124 lines
2.4 KiB
Go
124 lines
2.4 KiB
Go
package common
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import (
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"archive/zip"
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"encoding/json"
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"fmt"
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"io"
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"io/ioutil"
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"strings"
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)
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// Manifest object
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//
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// The manifest object holds all the relevant information supplied with the
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// the manifest specified in the package
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type Manifest struct {
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Entry string
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Height, Width int
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}
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// External package
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//
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// External package contains the main html file and manifest
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type ExtPackage struct {
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EntryHtml string
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Manifest *Manifest
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}
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// Read file
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//
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// Read a given compressed file and returns the read bytes.
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// Returns an error otherwise
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func ReadFile(f *zip.File) ([]byte, error) {
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rc, err := f.Open()
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if err != nil {
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return nil, err
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}
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defer rc.Close()
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content, err := ioutil.ReadAll(rc)
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if err != nil {
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return nil, err
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}
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return content, nil
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}
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// Reads manifest
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//
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// Reads and returns a manifest object. Returns error otherwise
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func ReadManifest(m []byte) (*Manifest, error) {
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var manifest Manifest
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dec := json.NewDecoder(strings.NewReader(string(m)))
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if err := dec.Decode(&manifest); err == io.EOF {
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} else if err != nil {
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return nil, err
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}
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return &manifest, nil
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}
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// Find file in archive
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//
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// Returns the index of the given file name if it exists. -1 if file not found
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func FindFileInArchive(fn string, files []*zip.File) (index int) {
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index = -1
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// Find the manifest first
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for i, f := range files {
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if f.Name == fn {
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index = i
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}
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}
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return
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}
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// Open package
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//
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// Opens a prepared ethereum package
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// Reads the manifest file and determines file contents and returns and
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// the external package.
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func OpenPackage(fn string) (*ExtPackage, error) {
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r, err := zip.OpenReader(fn)
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if err != nil {
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return nil, err
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}
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defer r.Close()
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manifestIndex := FindFileInArchive("manifest.json", r.File)
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if manifestIndex < 0 {
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return nil, fmt.Errorf("No manifest file found in archive")
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}
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f, err := ReadFile(r.File[manifestIndex])
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if err != nil {
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return nil, err
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}
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manifest, err := ReadManifest(f)
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if err != nil {
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return nil, err
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}
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if manifest.Entry == "" {
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return nil, fmt.Errorf("Entry file specified but appears to be empty: %s", manifest.Entry)
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}
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entryIndex := FindFileInArchive(manifest.Entry, r.File)
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if entryIndex < 0 {
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return nil, fmt.Errorf("Entry file not found: '%s'", manifest.Entry)
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}
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f, err = ReadFile(r.File[entryIndex])
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if err != nil {
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return nil, err
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}
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extPackage := &ExtPackage{string(f), manifest}
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return extPackage, nil
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}
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