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Fixing Evaluate and EvaluateAsDevTools actions

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- Update Evaluate action to also work with []byte
- Update Evaluate documentation
- Fix EvaluateAsDevTools action
- Refactor Query actions to use EvaluateAsDevTools
This commit is contained in:
Kenneth Shaw 2017-02-08 15:18:55 +07:00
parent 465e7becad
commit b57afce7e7
2 changed files with 69 additions and 101 deletions
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61
eval.go
View File

@ -8,12 +8,21 @@ import (
rundom "github.com/knq/chromedp/cdp/runtime"
)
// Evaluate evaluates the supplied Javascript expression, attempting to
// unmarshal the resulting value into res.
// Evaluate evaluates the Javascript expression, unmarshaling the result of the
// script evaluation to res.
//
// If res is a **chromedp/cdp/runtime.RemoteObject, then it will be set to the
// raw, returned RuntimeObject, Otherwise, the result value be json.Unmarshal'd
// to res.
// If res is *[]byte, then the result of the script evaluation will be returned
// "by value" (ie, JSON-encoded) and res will be set to the raw value.
//
// Alternatively, if res is **chromedp/cdp/runtime.RemoteObject, then it will
// be set to the returned RemoteObject and no attempt will be made to convert
// the value to an equivalent Go type.
//
// Otherwise, if res is any other Go type, the result of the script evaluation
// will be returned "by value" (ie, JSON-encoded), and subsequently will be
// json.Unmarshal'd into res.
//
// Note: any exception encountered will be returned as an error.
func Evaluate(expression string, res interface{}, opts ...EvaluateOption) Action {
if res == nil {
panic("res cannot be nil")
@ -22,12 +31,11 @@ func Evaluate(expression string, res interface{}, opts ...EvaluateOption) Action
return ActionFunc(func(ctxt context.Context, h cdp.FrameHandler) error {
var err error
// check if we want a 'raw' result
obj, raw := res.(**rundom.RemoteObject)
// set up parameters
p := rundom.Evaluate(expression)
if !raw {
switch res.(type) {
case **rundom.RemoteObject:
default:
p = p.WithReturnByValue(true)
}
@ -45,8 +53,13 @@ func Evaluate(expression string, res interface{}, opts ...EvaluateOption) Action
return exp
}
if raw {
*obj = v
switch x := res.(type) {
case **rundom.RemoteObject:
*x = v
return nil
case *[]byte:
*x = []byte(v.Value)
return nil
}
@ -55,39 +68,41 @@ func Evaluate(expression string, res interface{}, opts ...EvaluateOption) Action
})
}
// EvaluateAsDevTools is an action that evaluates a Javascript expression in
// the same context as Chrome DevTools would, exposing the Command Line API to
// the script evaluating the expression in the "console" context.
//
// Note: this should not be used with any untrusted code.
func EvaluateAsDevTools(expression string, res interface{}, opts ...EvaluateOption) Action {
return Evaluate(expression, res, append(opts, EvalObjectGroup("console"), EvalWithCommandLineAPI)...)
}
// EvaluateOption is an Evaluate call option.
type EvaluateOption func(*rundom.EvaluateParams) *rundom.EvaluateParams
// EvalObjectGroup is a Evaluate option to set the object group.
// EvalObjectGroup is a evaluate option to set the object group.
func EvalObjectGroup(objectGroup string) EvaluateOption {
return func(p *rundom.EvaluateParams) *rundom.EvaluateParams {
return p.WithObjectGroup(objectGroup)
}
}
// EvalWithCommandLineAPI is an Evaluate option to include the DevTools Command
// Line API.
// EvalWithCommandLineAPI is an evaluate option to make the DevTools Command
// Line API available to the evaluated script.
//
// Note: this should not be used with any untrusted code.
func EvalWithCommandLineAPI(p *rundom.EvaluateParams) *rundom.EvaluateParams {
return p.WithIncludeCommandLineAPI(true)
}
// EvalSilent is a Evaluate option that will cause script evaluation to ignore
// EvalSilent is a evaluate option that will cause script evaluation to ignore
// exceptions.
func EvalSilent(p *rundom.EvaluateParams) *rundom.EvaluateParams {
return p.WithSilent(true)
}
// EvalAsValue is a Evaluate option that will case the script to encode its
// EvalAsValue is a evaluate option that will case the script to encode its
// result as a value.
func EvalAsValue(p *rundom.EvaluateParams) *rundom.EvaluateParams {
return p.WithReturnByValue(true)
}
// EvaluateAsDevTools evaluates a Javascript expression in the same
//
// Note: this should not be used with any untrusted code.
func EvaluateAsDevTools(expression string) Action {
return Evaluate(expression, EvalObjectGroup("console"), EvalWithCommandLineAPI)
}

109
query.go
View File

@ -3,7 +3,6 @@ package chromedp
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"image"
@ -16,7 +15,6 @@ import (
"github.com/knq/chromedp/cdp/dom"
"github.com/knq/chromedp/cdp/input"
"github.com/knq/chromedp/cdp/page"
rundom "github.com/knq/chromedp/cdp/runtime"
)
var (
@ -128,29 +126,13 @@ func Value(sel interface{}, value *string, opts ...QueryOption) Action {
if value == nil {
panic("value cannot be nil")
}
return QueryAfter(sel, func(ctxt context.Context, h cdp.FrameHandler, nodes ...*cdp.Node) error {
if len(nodes) < 1 {
return fmt.Errorf("selector `%s` did not return any nodes", sel)
}
p := rundom.Evaluate(fmt.Sprintf(valueJS, nodes[0].FullXPath()))
p.IncludeCommandLineAPI = true
p.ObjectGroup = "console"
res, exp, err := p.Do(ctxt, h)
if err != nil {
return err
}
if exp != nil {
return exp
}
if res.Type != rundom.TypeString || len(res.Value) < 2 {
return fmt.Errorf("expected string of at least length 2, got %s length %d", res.Subtype, len(res.Value))
}
*value = string(res.Value[1 : len(res.Value)-1])
return nil
return EvaluateAsDevTools(fmt.Sprintf(valueJS, nodes[0].FullXPath()), value).Do(ctxt, h)
}, opts...)
}
@ -161,19 +143,13 @@ func SetValue(sel interface{}, value string, opts ...QueryOption) Action {
return fmt.Errorf("selector `%s` did not return any nodes", sel)
}
p := rundom.Evaluate(fmt.Sprintf(setValueJS, nodes[0].FullXPath(), value))
p.IncludeCommandLineAPI = true
p.ObjectGroup = "console"
res, exp, err := p.Do(ctxt, h)
var res string
err := EvaluateAsDevTools(fmt.Sprintf(setValueJS, nodes[0].FullXPath(), value), &res).Do(ctxt, h)
if err != nil {
return err
}
if exp != nil {
return exp
}
if res.Type != rundom.TypeString || len(res.Value) < 2 {
return fmt.Errorf("expected string of at least length 2, got %s length %d", res.Subtype, len(res.Value))
if res != value {
return fmt.Errorf("could not set value on node %d", nodes[0].NodeID)
}
return nil
@ -190,24 +166,7 @@ func Text(sel interface{}, text *string, opts ...QueryOption) Action {
return fmt.Errorf("selector `%s` did not return any nodes", sel)
}
p := rundom.Evaluate(fmt.Sprintf(textJS, nodes[0].FullXPath()))
p.IncludeCommandLineAPI = true
p.ObjectGroup = "console"
res, exp, err := p.Do(ctxt, h)
if err != nil {
return err
}
if exp != nil {
return exp
}
if res.Type != rundom.TypeString || len(res.Value) < 2 {
return fmt.Errorf("expected string of at least length 2, got %s length %d", res.Subtype, len(res.Value))
}
*text = string(res.Value[1 : len(res.Value)-1])
return nil
return EvaluateAsDevTools(fmt.Sprintf(textJS, nodes[0].FullXPath()), text).Do(ctxt, h)
}, opts...)
}
@ -372,21 +331,9 @@ func Screenshot(sel interface{}, picbuf *[]byte, opts ...QueryOption) Action {
return ErrInvalidBoxModel
}
// evaluate scroll script
res, exp, err := rundom.Evaluate(fmt.Sprintf(scrollJS, int64(box.Margin[0]), int64(box.Margin[1]))).Do(ctxt, h)
if err != nil {
return err
}
if exp != nil {
return exp
}
if res.Type != rundom.TypeString || len(res.Value) < 2 {
return fmt.Errorf("expected string of at least length 2, got %s length %d", res.Subtype, len(res.Value))
}
// parse response
var scroll []int
err = json.Unmarshal([]byte(res.Value[1:len(res.Value)-1]), &scroll)
// scroll to node location
var pos []int
err = EvaluateAsDevTools(fmt.Sprintf(scrollJS, int64(box.Margin[0]), int64(box.Margin[1])), &pos).Do(ctxt, h)
if err != nil {
return err
}
@ -405,8 +352,8 @@ func Screenshot(sel interface{}, picbuf *[]byte, opts ...QueryOption) Action {
// crop to box model contents.
cropped := imaging.Crop(img, image.Rect(
int(box.Margin[0])-scroll[0], int(box.Margin[1])-scroll[1],
int(box.Margin[4])-scroll[0], int(box.Margin[5])-scroll[1],
int(box.Margin[0])-pos[0], int(box.Margin[1])-pos[1],
int(box.Margin[4])-pos[0], int(box.Margin[5])-pos[1],
))
// encode
@ -429,19 +376,14 @@ func Submit(sel interface{}, opts ...QueryOption) Action {
return fmt.Errorf("selector `%s` did not return any nodes", sel)
}
p := rundom.Evaluate(fmt.Sprintf(submitJS, nodes[0].FullXPath()))
p.IncludeCommandLineAPI = true
p.ObjectGroup = "console"
res, exp, err := p.Do(ctxt, h)
var res bool
err := EvaluateAsDevTools(fmt.Sprintf(submitJS, nodes[0].FullXPath()), &res).Do(ctxt, h)
if err != nil {
return err
}
if exp != nil {
return exp
}
if res.Type != rundom.TypeString || len(res.Value) < 2 {
return fmt.Errorf("expected string of at least length 2, got %s length %d", res.Subtype, len(res.Value))
if !res {
return fmt.Errorf("submit on node %d returned false", nodes[0].NodeID)
}
return nil
@ -449,6 +391,8 @@ func Submit(sel interface{}, opts ...QueryOption) Action {
}
const (
// textJS is a javascript snippet that returns the concatenated textContent
// of all visible (ie, offsetParent !== null) children.
textJS = `(function(a) {
var s = '';
for (var i = 0; i < a.length; i++) {
@ -459,22 +403,31 @@ const (
return s;
})($x("%s/node()"))`
// scrollJS is a javascript snippet that scrolls the window to the
// specified x, y coordinates and then returns the actual window x/y after
// execution.
scrollJS = `(function(x, y) {
window.scrollTo(x, y);
return '['+window.scrollX+','+window.scrollY+']';
return [window.scrollX, window.scrollY];
})(%d, %d)`
// submitJS is a javascript snippet that will call the containing form's
// submit function, returning true or false if the call was successful.
submitJS = `(function(a) {
if (a[0].form !== null) {
return "" + a[0].form.submit();
return a[0].form.submit();
}
return 'false';
return false;
})($x('%s'))`
// valueJS is a javascript snippet that returns the value of a specified
// node.
valueJS = `(function(a) {
return a[0].value;
})($x('%s'))`
// setValueJS is a javascript snippet that sets the value of the specified
// node, and returns the value.
setValueJS = `(function(a, val) {
return a[0].value = val;
})($x('%s'), '%s')`