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author | obscuren <geffobscura@gmail.com> | 2014-04-23 17:50:17 +0800 |
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committer | obscuren <geffobscura@gmail.com> | 2014-04-23 17:50:17 +0800 |
commit | 11c26e32114dabc6524ad9fb1f868440f5d3fff3 (patch) | |
tree | 32bab7cf0040aa0f4ee4dabcd077b7134601af8e /ethutil | |
parent | 6930260962f4c6d1fe11d07a10300da96886ecd6 (diff) | |
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Implemented ethereum package reader
Diffstat (limited to 'ethutil')
-rw-r--r-- | ethutil/package.go | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/ethutil/package.go b/ethutil/package.go new file mode 100644 index 000000000..e5df989d2 --- /dev/null +++ b/ethutil/package.go @@ -0,0 +1,123 @@ +package ethutil + +import ( + "archive/zip" + "encoding/json" + "fmt" + "io" + "io/ioutil" + "strings" +) + +// Manifest object +// +// The manifest object holds all the relevant information supplied with the +// the manifest specified in the package +type Manifest struct { + Entry string + Height, Width int +} + +// External package +// +// External package contains the main html file and manifest +type ExtPackage struct { + EntryHtml string + Manifest *Manifest +} + +// Read file +// +// Read a given compressed file and returns the read bytes. +// Returns an error otherwise +func ReadFile(f *zip.File) ([]byte, error) { + rc, err := f.Open() + if err != nil { + return nil, err + } + defer rc.Close() + + content, err := ioutil.ReadAll(rc) + if err != nil { + return nil, err + } + + return content, nil +} + +// Reads manifest +// +// Reads and returns a manifest object. Returns error otherwise +func ReadManifest(m []byte) (*Manifest, error) { + var manifest Manifest + + dec := json.NewDecoder(strings.NewReader(string(m))) + if err := dec.Decode(&manifest); err == io.EOF { + } else if err != nil { + return nil, err + } + + return &manifest, nil +} + +// Find file in archive +// +// Returns the index of the given file name if it exists. -1 if file not found +func FindFileInArchive(fn string, files []*zip.File) (index int) { + index = -1 + // Find the manifest first + for i, f := range files { + if f.Name == fn { + index = i + } + } + + return +} + +// Open package +// +// Opens a prepared ethereum package +// Reads the manifest file and determines file contents and returns and +// the external package. +func OpenPackage(fn string) (*ExtPackage, error) { + r, err := zip.OpenReader(fn) + if err != nil { + return nil, err + } + defer r.Close() + + manifestIndex := FindFileInArchive("manifest.json", r.File) + + if manifestIndex < 0 { + return nil, fmt.Errorf("No manifest file found in archive") + } + + f, err := ReadFile(r.File[manifestIndex]) + if err != nil { + return nil, err + } + + manifest, err := ReadManifest(f) + if err != nil { + return nil, err + } + + if manifest.Entry == "" { + return nil, fmt.Errorf("Entry file specified but appears to be empty: %s", manifest.Entry) + } + + entryIndex := FindFileInArchive(manifest.Entry, r.File) + if entryIndex < 0 { + return nil, fmt.Errorf("Entry file not found: '%s'", manifest.Entry) + } + + f, err = ReadFile(r.File[entryIndex]) + if err != nil { + return nil, err + } + + extPackage := &ExtPackage{string(f), manifest} + + return extPackage, nil +} |