From 7e4cf39a0ba6ccbd5cc036700a8b1ff9358ecc3d Mon Sep 17 00:00:00 2001
From: Philipp Tanlak <philipp.tanlak@gmail.com>
Date: Thu, 10 Aug 2023 18:18:01 +0200
Subject: improve

---
 js/js.go | 102 +++++++++++++++++++++++++--------------------------------------
 1 file changed, 41 insertions(+), 61 deletions(-)

(limited to 'js/js.go')

diff --git a/js/js.go b/js/js.go
index c5b8818..dd9c7a1 100644
--- a/js/js.go
+++ b/js/js.go
@@ -6,9 +6,10 @@ import (
 	"fmt"
 	"math/rand"
 	"os"
-	"path/filepath"
+	"strings"
 	"time"
 
+	"flyscrape/flyscrape"
 	"flyscrape/js/jsbundle"
 
 	"github.com/evanw/esbuild/pkg/api"
@@ -19,53 +20,23 @@ func init() {
 	rand.Seed(time.Now().UnixNano())
 }
 
-type RunOptions struct {
-	HTML string
-}
-
-type RunFunc func(RunOptions) any
-
-type Options struct {
-	URL string `json:"url"`
-}
-
-func Compile(file string) (*Options, RunFunc, error) {
+func Compile(file string) (*flyscrape.ScrapeOptions, flyscrape.ScrapeFunc, error) {
 	src, err := build(file)
 	if err != nil {
 		return nil, nil, err
 	}
-	os.WriteFile("out.js", []byte(src), 0o644)
 	return vm(src)
 }
 
 func build(file string) (string, error) {
-	dir, err := os.MkdirTemp("", "flyscrape")
+	data, err := os.ReadFile(file)
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("read %q: %w", file, err)
 	}
-	defer os.RemoveAll(dir)
 
-	tmpfile := filepath.Join(dir, "flyscrape.js")
-	if err := os.WriteFile(tmpfile, jsbundle.Flyscrape, 0o644); err != nil {
-		return "", err
-	}
-
-	resolve := api.Plugin{
-		Name: "flyscrape",
-		Setup: func(build api.PluginBuild) {
-			build.OnResolve(api.OnResolveOptions{
-				Filter: "^flyscrape$",
-			}, func(ora api.OnResolveArgs) (api.OnResolveResult, error) {
-				return api.OnResolveResult{Path: tmpfile}, nil
-			})
-		},
-	}
-
-	res := api.Build(api.BuildOptions{
-		EntryPoints: []string{file},
-		Bundle:      true,
-		Platform:    api.PlatformNode,
-		Plugins:     []api.Plugin{resolve},
+	res := api.Transform(string(data), api.TransformOptions{
+		Platform: api.PlatformBrowser,
+		Format:   api.FormatIIFE,
 	})
 
 	var errs []error
@@ -76,51 +47,54 @@ func build(file string) (string, error) {
 		return "", errors.Join(errs...)
 	}
 
-	out := string(res.OutputFiles[0].Contents)
-	return out, nil
+	return string(res.Code), nil
 }
 
-func vm(src string) (*Options, RunFunc, error) {
-	os.WriteFile("out.js", []byte(src), 0o644)
-
+func vm(src string) (*flyscrape.ScrapeOptions, flyscrape.ScrapeFunc, error) {
 	ctx := v8.NewContext()
 	ctx.RunScript("var module = {}", "main.js")
-	if _, err := ctx.RunScript(src, "main.js"); err != nil {
+
+	if _, err := ctx.RunScript(removeIIFE(jsbundle.Flyscrape), "main.js"); err != nil {
 		return nil, nil, fmt.Errorf("run bundled js: %w", err)
 	}
-
-	val, err := ctx.RunScript("module.exports.options", "main.js")
-	if err != nil {
-		return nil, nil, fmt.Errorf("export options: %w", err)
+	if _, err := ctx.RunScript(`const require = () => require_flyscrape();`, "main.js"); err != nil {
+		return nil, nil, fmt.Errorf("define require: %w", err)
 	}
-	options, err := val.AsObject()
-	if err != nil {
-		return nil, nil, fmt.Errorf("cast options as object: %w", err)
+	if _, err := ctx.RunScript(removeIIFE(src), "main.js"); err != nil {
+		return nil, nil, fmt.Errorf("userscript: %w", err)
 	}
 
-	var opts Options
-	url, err := options.Get("url")
+	var opts flyscrape.ScrapeOptions
+
+	url, err := ctx.RunScript("options.url", "main.js")
 	if err != nil {
-		return nil, nil, fmt.Errorf("getting url from options: %w", err)
+		return nil, nil, fmt.Errorf("eval: options.url: %w", err)
 	}
 	opts.URL = url.String()
 
-	run := func(ro RunOptions) any {
+	depth, err := ctx.RunScript("options.depth", "main.js")
+	if err != nil {
+		return nil, nil, fmt.Errorf("eval: options.depth: %w", err)
+	}
+	opts.Depth = int(depth.Integer())
+
+	scrape := func(params flyscrape.ScrapeParams) (flyscrape.M, error) {
 		suffix := randSeq(10)
-		ctx.Global().Set("html_"+suffix, ro.HTML)
-		data, err := ctx.RunScript(fmt.Sprintf(`JSON.stringify(module.exports.default({html: html_%s}))`, suffix), "main.js")
+		ctx.Global().Set("html_"+suffix, params.HTML)
+		data, err := ctx.RunScript(fmt.Sprintf(`JSON.stringify(stdin_default({html: html_%s}))`, suffix), "main.js")
 		if err != nil {
-			return err.Error()
+			return nil, err
 		}
 
-		var obj any
+		var obj flyscrape.M
 		if err := json.Unmarshal([]byte(data.String()), &obj); err != nil {
-			return err.Error()
+			return nil, err
 		}
 
-		return obj
+		return obj, nil
 	}
-	return &opts, run, nil
+
+	return &opts, scrape, nil
 }
 
 func randSeq(n int) string {
@@ -131,3 +105,9 @@ func randSeq(n int) string {
 	}
 	return string(b)
 }
+
+func removeIIFE(s string) string {
+	s = strings.TrimPrefix(s, "(() => {\n")
+	s = strings.TrimSuffix(s, "})();\n")
+	return s
+}
-- 
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