/
display.go
349 lines (321 loc) · 8.12 KB
/
display.go
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package main
import (
"bytes"
"errors"
"fmt"
"image"
"io"
"io/ioutil"
"net/http"
"strings"
)
// Support an interface similar - but not identical - to the IPython (canonical Jupyter kernel).
// See http://ipython.readthedocs.io/en/stable/api/generated/IPython.display.html#IPython.display.display
// for a good overview of the support types.
const (
MIMETypeHTML = "text/html"
MIMETypeJavaScript = "application/javascript"
MIMETypeJPEG = "image/jpeg"
MIMETypeJSON = "application/json"
MIMETypeLatex = "text/latex"
MIMETypeMarkdown = "text/markdown"
MIMETypePNG = "image/png"
MIMETypePDF = "application/pdf"
MIMETypeSVG = "image/svg+xml"
MIMETypeText = "text/plain"
)
/**
* general interface, allows libraries to fully specify
* how their data is displayed by Jupyter.
* Supports multiple MIME formats.
*
* Note that Data defined above is an alias:
* libraries can implement Renderer without importing gophernotes
*/
type Renderer = interface {
Render() Data
}
/**
* simplified interface, allows libraries to specify
* how their data is displayed by Jupyter.
* Supports multiple MIME formats.
*
* Note that MIMEMap defined above is an alias:
* libraries can implement SimpleRenderer without importing gophernotes
*/
type SimpleRenderer = interface {
SimpleRender() MIMEMap
}
/**
* specialized interfaces, each is dedicated to a specific MIME type.
*
* They are type aliases to emphasize that method signatures
* are the only important thing, not the interface names.
* Thus libraries can implement them without importing gophernotes
*/
type HTMLer = interface {
HTML() string
}
type JavaScripter = interface {
JavaScript() string
}
type JPEGer = interface {
JPEG() []byte
}
type JSONer = interface {
JSON() map[string]interface{}
}
type Latexer = interface {
Latex() string
}
type Markdowner = interface {
Markdown() string
}
type PNGer = interface {
PNG() []byte
}
type PDFer = interface {
PDF() []byte
}
type SVGer = interface {
SVG() string
}
// injected as placeholder in the interpreter, it's then replaced at runtime
// by a closure that knows how to talk with Jupyter
func stubDisplay(Data) error {
return errors.New("cannot display: connection with Jupyter not available")
}
// if vals[] contain a single non-nil value which is auto-renderable,
// convert it to Data and return it.
// otherwise return MakeData("text/plain", fmt.Sprint(vals...))
func autoRenderResults(vals []interface{}) Data {
return MakeData(MIMETypeText, fmt.Sprint(vals...))
}
var autoRenderers = map[string]func(Data, interface{}) Data{
"Renderer": func(d Data, i interface{}) Data {
if r, ok := i.(Renderer); ok {
x := r.Render()
d.Data = merge(d.Data, x.Data)
d.Metadata = merge(d.Metadata, x.Metadata)
d.Transient = merge(d.Transient, x.Transient)
}
return d
},
"SimpleRenderer": func(d Data, i interface{}) Data {
if r, ok := i.(SimpleRenderer); ok {
x := r.SimpleRender()
d.Data = merge(d.Data, x)
}
return d
},
"HTMLer": func(d Data, i interface{}) Data {
if r, ok := i.(HTMLer); ok {
d.Data = ensure(d.Data)
d.Data[MIMETypeHTML] = r.HTML()
}
return d
},
"JavaScripter": func(d Data, i interface{}) Data {
if r, ok := i.(JavaScripter); ok {
d.Data = ensure(d.Data)
d.Data[MIMETypeJavaScript] = r.JavaScript()
}
return d
},
"JPEGer": func(d Data, i interface{}) Data {
if r, ok := i.(JPEGer); ok {
d.Data = ensure(d.Data)
d.Data[MIMETypeJPEG] = r.JPEG()
}
return d
},
"JSONer": func(d Data, i interface{}) Data {
if r, ok := i.(JSONer); ok {
d.Data = ensure(d.Data)
d.Data[MIMETypeJSON] = r.JSON()
}
return d
},
"Latexer": func(d Data, i interface{}) Data {
if r, ok := i.(Latexer); ok {
d.Data = ensure(d.Data)
d.Data[MIMETypeLatex] = r.Latex()
}
return d
},
"Markdowner": func(d Data, i interface{}) Data {
if r, ok := i.(Markdowner); ok {
d.Data = ensure(d.Data)
d.Data[MIMETypeMarkdown] = r.Markdown()
}
return d
},
"PNGer": func(d Data, i interface{}) Data {
if r, ok := i.(PNGer); ok {
d.Data = ensure(d.Data)
d.Data[MIMETypePNG] = r.PNG()
}
return d
},
"PDFer": func(d Data, i interface{}) Data {
if r, ok := i.(PDFer); ok {
d.Data = ensure(d.Data)
d.Data[MIMETypePDF] = r.PDF()
}
return d
},
"SVGer": func(d Data, i interface{}) Data {
if r, ok := i.(SVGer); ok {
d.Data = ensure(d.Data)
d.Data[MIMETypeSVG] = r.SVG()
}
return d
},
"Image": func(d Data, i interface{}) Data {
if r, ok := i.(image.Image); ok {
b, mimeType, err := encodePng(r)
if err != nil {
d = makeDataErr(err)
} else {
d.Data = ensure(d.Data)
d.Data[mimeType] = b
d.Metadata = merge(d.Metadata, imageMetadata(r))
}
}
return d
},
}
// detect and render data types that should be auto-rendered graphically
func fillDefaults(data Data, arg interface{}, s string, b []byte, mimeType string, err error) Data {
if err != nil {
return makeDataErr(err)
}
if data.Data == nil {
data.Data = make(MIMEMap)
}
// cannot autodetect the mime type of a string
if len(s) != 0 && len(mimeType) != 0 {
data.Data[mimeType] = s
}
// ensure plain text is set
if data.Data[MIMETypeText] == "" {
if len(s) == 0 {
s = fmt.Sprint(arg)
}
data.Data[MIMETypeText] = s
}
// if []byte is available, use it
if len(b) != 0 {
if len(mimeType) == 0 {
mimeType = http.DetectContentType(b)
}
if len(mimeType) != 0 && mimeType != MIMETypeText {
data.Data[mimeType] = b
}
}
return data
}
// do our best to render data graphically
func render(mimeType string, data interface{}) Data {
var s string
var b []byte
var err error
switch data := data.(type) {
case string:
s = data
case []byte:
b = data
case io.Reader:
b, err = ioutil.ReadAll(data)
case io.WriterTo:
var buf bytes.Buffer
data.WriteTo(&buf)
b = buf.Bytes()
default:
panic(fmt.Errorf("unsupported type, cannot render: %T", data))
}
return fillDefaults(Data{}, data, s, b, mimeType, err)
}
func makeDataErr(err error) Data {
return Data{
Data: MIMEMap{
"ename": "ERROR",
"evalue": err.Error(),
"traceback": nil,
"status": "error",
},
}
}
func Any(mimeType string, data interface{}) Data {
return render(mimeType, data)
}
// same as Any("", data), autodetects MIME type
func Auto(data interface{}) Data {
return render("", data)
}
func MakeData(mimeType string, data interface{}) Data {
d := Data{
Data: MIMEMap{
mimeType: data,
},
}
if mimeType != MIMETypeText {
d.Data[MIMETypeText] = fmt.Sprint(data)
}
return d
}
func MakeData3(mimeType string, plaintext string, data interface{}) Data {
return Data{
Data: MIMEMap{
MIMETypeText: plaintext,
mimeType: data,
},
}
}
func File(mimeType string, path string) Data {
bytes, err := ioutil.ReadFile(path)
if err != nil {
panic(err)
}
return Any(mimeType, bytes)
}
func HTML(html string) Data {
return MakeData(MIMETypeHTML, html)
}
func JavaScript(javascript string) Data {
return MakeData(MIMETypeJavaScript, javascript)
}
func JPEG(jpeg []byte) Data {
return MakeData(MIMETypeJPEG, jpeg)
}
func JSON(json map[string]interface{}) Data {
return MakeData(MIMETypeJSON, json)
}
func Latex(latex string) Data {
return MakeData3(MIMETypeLatex, latex, "$"+strings.Trim(latex, "$")+"$")
}
func Markdown(markdown string) Data {
return MakeData(MIMETypeMarkdown, markdown)
}
func Math(latex string) Data {
return MakeData3(MIMETypeLatex, latex, "$$"+strings.Trim(latex, "$")+"$$")
}
func PDF(pdf []byte) Data {
return MakeData(MIMETypePDF, pdf)
}
func PNG(png []byte) Data {
return MakeData(MIMETypePNG, png)
}
func SVG(svg string) Data {
return MakeData(MIMETypeSVG, svg)
}
// MIME encapsulates the data and metadata into a Data.
// The 'data' map is expected to contain at least one {key,value} pair,
// with value being a string, []byte or some other JSON serializable representation,
// and key equal to the MIME type of such value.
// The exact structure of value is determined by what the frontend expects.
// Some easier-to-use functions for common formats supported by the Jupyter frontend
// are provided by the various functions above.
func MIME(data, metadata MIMEMap) Data {
return Data{data, metadata, nil}
}