added support for azw3 -> epub conversion

src/CommonFormats.ts

@@ -214,6 +214,27 @@ const CommonFormats = {
         "application/pdf",
         Category.DOCUMENT
     ),
+    EPUB: new FormatDefinition(
+        "Electronic Publication",
+        "epub",
+        "epub",
+        "application/epub+zip",
+        Category.DOCUMENT
+    ),
+    AZW3: new FormatDefinition(
+        "Amazon Kindle Format 8",
+        "azw3",
+        "azw3",
+        "application/vnd.amazon.mobi8-ebook",
+        Category.DOCUMENT
+    ),
+    MOBI: new FormatDefinition(
+        "Mobipocket e-book",
+        "mobi",
+        "mobi",
+        "application/x-mobipocket-ebook",
+        Category.DOCUMENT
+    ),
     // documents - Microsoft Office
     DOCX: new FormatDefinition(
         "WordprocessingML Document",

src/handlers/azw3.ts

@@ -0,0 +1,172 @@
+import type { FileData, FileFormat, FormatHandler } from "../FormatHandler.ts";
+import CommonFormats from "src/CommonFormats.ts";
+import JSZip from "jszip";
+import pako from "pako";
+import { isMOBI, MOBI } from "./azw3/mobi.js";
+
+class azw3Handler implements FormatHandler {
+
+    public name: string = "azw3";
+    public supportedFormats?: FileFormat[];
+    public ready: boolean = false;
+
+    async init () {
+        this.supportedFormats = [
+            CommonFormats.AZW3.supported("azw3", true, false),
+            CommonFormats.MOBI.supported("mobi", true, false),
+            CommonFormats.EPUB.supported("epub", false, true)
+        ];
+        this.ready = true;
+    }
+
+    async doConvert (
+        inputFiles: FileData[],
+        inputFormat: FileFormat,
+        outputFormat: FileFormat
+    ): Promise<FileData[]> {
+        const outputFiles: FileData[] = [];
+        for (const inputFile of inputFiles) {
+            const blob = new Blob([new Uint8Array(inputFile.bytes)]);
+            const valid = await isMOBI(blob);
+            if (!valid) throw new Error("Invalid MOBI/AZW3 file.");
+
+            const book = await new MOBI({ unzlib: pako.inflate }).open(blob);
+            const metadata = book.metadata;
+
+            const zip = new JSZip();
+            zip.file("mimetype", "application/epub+zip");
+
+            const metaInf = zip.folder("META-INF")!;
+            metaInf.file("container.xml", `<?xml version="1.0" encoding="UTF-8"?>
+<container version="1.0" xmlns="urn:oasis:names:tc:opendocument:xmlns:container">
+    <rootfiles>
+        <rootfile full-path="OEBPS/content.opf" media-type="application/oebps-package+xml"/>
+    </rootfiles>
+</container>`);
+
+            const oebps = zip.folder("OEBPS")!;
+            const manifest: string[] = [];
+            const spine: string[] = [];
+
+            const serializer = new XMLSerializer();
+
+            let itemIndex = 0;
+
+            for (let i = 0; i < book.sections.length; i++) {
+                const section = book.sections[i];
+                const isLinear = section.linear !== 'no';
+
+                try {
+                    const doc = await section.createDocument?.() as Document;
+                    if (!doc) continue;
+
+                    // Images handling
+                    for (const img of Array.from(doc.querySelectorAll('img'))) {
+                        const recindex = img.getAttribute('recindex');
+                        let b64 = null;
+                        let type = "image/jpeg";
+
+                        if (recindex != null) {
+                            try {
+                                const buf = await book.mobi.loadResource(Number(recindex) - 1);
+                                const uint8 = new Uint8Array(buf as ArrayBuffer);
+                                let binary = '';
+                                for (let j = 0; j < uint8.byteLength; j++) {
+                                    binary += String.fromCharCode(uint8[j]);
+                                }
+                                b64 = btoa(binary);
+                            } catch (e) {
+                                console.warn(e);
+                            }
+                        } else {
+                            const src = img.getAttribute('src');
+                            if (src && src.startsWith('kindle:embed:')) {
+                                try {
+                                    const [b, inline] = await (book as any).loadResourceBlob(src);
+                                    if (b) {
+                                        type = b.type;
+                                        const arrayBuffer = await b.arrayBuffer();
+                                        const uint8 = new Uint8Array(arrayBuffer);
+                                        let binary = '';
+                                        for (let j = 0; j < uint8.byteLength; j++) {
+                                            binary += String.fromCharCode(uint8[j]);
+                                        }
+                                        b64 = btoa(binary);
+                                    }
+                                } catch (e) {
+                                    console.warn(e);
+                                }
+                            }
+                        }
+
+                        if (b64) {
+                            img.src = `data:${type};base64,` + b64;
+                        }
+                    }
+
+                    const html = `<?xml version="1.0" encoding="utf-8"?>\n<!DOCTYPE html>\n` + serializer.serializeToString(doc);
+                    const filename = `part${itemIndex}.xhtml`;
+                    oebps.file(filename, html);
+
+                    manifest.push(`<item id="item${itemIndex}" href="${filename}" media-type="application/xhtml+xml" />`);
+                    spine.push(`<itemref idref="item${itemIndex}" ${isLinear ? '' : 'linear="no" '}/>`);
+                    itemIndex++;
+
+                } catch (e) {
+                    console.warn("Failed section", e);
+                }
+            }
+
+            // Create content.opf
+            const opf = `<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid">
+    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
+        <dc:title>${metadata?.title || "Unknown Book"}</dc:title>
+        <dc:language>${metadata?.language || "en"}</dc:language>
+        <dc:identifier id="uid">${metadata?.identifier || Date.now()}</dc:identifier>
+        ${metadata?.author ? metadata.author.map((a: string) => `<dc:creator>${a}</dc:creator>`).join('') : ''}
+    </metadata>
+    <manifest>
+        ${manifest.join('\\n        ')}
+        <item id="ncx" href="toc.ncx" media-type="application/x-dtbncx+xml"/>
+    </manifest>
+    <spine toc="ncx">
+        ${spine.join('\\n        ')}
+    </spine>
+</package>`;
+
+            oebps.file("content.opf", opf);
+
+            // Create dummy toc.ncx
+            const ncx = `<?xml version="1.0" encoding="UTF-8"?>
+<ncx xmlns="http://www.daisy.org/z3986/2005/ncx/" version="2005-1">
+    <head>
+        <meta name="dtb:uid" content="${metadata?.identifier || Date.now()}"/>
+        <meta name="dtb:depth" content="1"/>
+        <meta name="dtb:totalPageCount" content="0"/>
+        <meta name="dtb:maxPageNumber" content="0"/>
+    </head>
+    <docTitle>
+        <text>${metadata?.title || "Unknown Book"}</text>
+    </docTitle>
+    <navMap>
+        <navPoint id="navPoint-1" playOrder="1">
+            <navLabel><text>Start</text></navLabel>
+            <content src="part0.html"/>
+        </navPoint>
+    </navMap>
+</ncx>`;
+            oebps.file("toc.ncx", ncx);
+
+            const epubBlob = await zip.generateAsync({ type: "uint8array" });
+            const outputName = inputFile.name.split(".").slice(0, -1).join(".") + ".epub";
+            outputFiles.push({
+                name: outputName,
+                bytes: epubBlob
+            });
+        }
+        return outputFiles;
+    }
+}
+
+export default azw3Handler;