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ferret/pkg/stdlib/html/pagination.go
Tim Voronov 90427cd537
Feature/new selector type (#657)
* Added remote type reference resolver

* Added support of XPath query selector

* Added CDP e2e testss covering XPath integration

* Added additional CDP e2e tests covering XPath integration

* Added type check to QuerySelector casting function

* Fixed XPath e2e tests

* Fixed vuln issue

* Added support of XPath selectors to http driver

* Added e2e tests for XPAth
2021-09-16 21:40:20 -04:00

133 lines
3.1 KiB
Go

package html
import (
"context"
"github.com/MontFerret/ferret/pkg/drivers"
"github.com/MontFerret/ferret/pkg/runtime/core"
"github.com/MontFerret/ferret/pkg/runtime/logging"
"github.com/MontFerret/ferret/pkg/runtime/values"
"github.com/rs/zerolog"
)
// PAGINATION creates an iterator that goes through pages using CSS selector.
// The iterator starts from the current page i.e. it does not change the page on 1st iteration.
// That allows you to keep scraping logic inside FOR loop.
// @param {HTMLPage | HTMLDocument | HTMLElement} node - Target html node.
// @param {String} selector - CSS selector for a pagination on the page.
func Pagination(ctx context.Context, args ...core.Value) (core.Value, error) {
err := core.ValidateArgs(args, 2, 2)
if err != nil {
return values.None, err
}
page, err := drivers.ToPage(args[0])
if err != nil {
return values.None, err
}
selector, err := drivers.ToQuerySelector(args[1])
if err != nil {
return values.None, err
}
logger := logging.
WithName(logging.FromContext(ctx).With(), "stdlib_html_pagination").
Str("selector", selector.String()).
Logger()
return &Paging{logger, page, selector}, nil
}
var PagingType = core.NewType("paging")
type (
Paging struct {
logger zerolog.Logger
page drivers.HTMLPage
selector drivers.QuerySelector
}
PagingIterator struct {
logger zerolog.Logger
page drivers.HTMLPage
selector drivers.QuerySelector
pos values.Int
}
)
func (p *Paging) MarshalJSON() ([]byte, error) {
return nil, core.ErrInvalidOperation
}
func (p *Paging) Type() core.Type {
return PagingType
}
func (p *Paging) String() string {
return PagingType.String()
}
func (p *Paging) Compare(_ core.Value) int64 {
return 1
}
func (p *Paging) Unwrap() interface{} {
return nil
}
func (p *Paging) Hash() uint64 {
return 0
}
func (p *Paging) Copy() core.Value {
return values.None
}
func (p *Paging) Iterate(_ context.Context) (core.Iterator, error) {
return &PagingIterator{p.logger, p.page, p.selector, -1}, nil
}
func (i *PagingIterator) Next(ctx context.Context) (core.Value, core.Value, error) {
i.pos++
i.logger.Trace().Int("position", int(i.pos)).Msg("starting to advance iteration")
if i.pos == 0 {
i.logger.Trace().Msg("starting point of pagination. nothing to do. exit")
return values.ZeroInt, values.ZeroInt, nil
}
i.logger.Trace().Msg("checking if an element exists...")
exists, err := i.page.GetMainFrame().ExistsBySelector(ctx, i.selector)
if err != nil {
i.logger.Trace().Err(err).Msg("failed to check")
return values.None, values.None, err
}
if !exists {
i.logger.Trace().Bool("exists", bool(exists)).Msg("element does not exist. exit")
return values.None, values.None, core.ErrNoMoreData
}
i.logger.Trace().Bool("exists", bool(exists)).Msg("element exists. clicking...")
err = i.page.GetMainFrame().GetElement().ClickBySelector(ctx, i.selector, 1)
if err != nil {
i.logger.Trace().Err(err).Msg("failed to click. exit")
return values.None, values.None, err
}
i.logger.Trace().Msg("successfully clicked on element. iteration has succeeded")
// terminate
return i.pos, i.pos, nil
}