first version

.gitignore

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+__pycache__/
+# test epub files
+*.epub

convert.py

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+import argparse
+import zipfile
+import opencc
+import glob
+import time
+from io import BytesIO
+from pathlib import Path
+
+# only initailize OpenCC once, or it would be very slow
+converter = opencc.OpenCC(config="s2twp.json")
+
+def convert_epub(epub, output=None):
+    target_filetype = ["htm", "html", "xhtml", "ncx", "opf"]
+
+    origin = zipfile.ZipFile(epub, mode="r")
+    copy = zipfile.ZipFile(output, mode="w")
+
+    for i, fn in enumerate(origin.namelist()):
+        info = origin.getinfo(fn)
+        extension = Path(fn).suffix[1:] # remove heading `.`
+        if extension in target_filetype:
+            # if file extension is targeted file type
+            sc_content = origin.read(fn)
+            tc_content = convert_content(sc_content)
+            if extension == "opf":
+                tc_content = tc_content.replace("<dc:language>zh-CN</dc:language>", "<dc:language>zh-TW</dc:language>")
+            copy.writestr(s2t(fn), tc_content, compress_type=info.compress_type)
+        else:
+            # write other files directly
+            copy.writestr(s2t(fn), origin.read(fn), compress_type=info.compress_type)
+
+    origin.close()
+    copy.close()
+    return output
+
+def convert_content(content):
+    _tmp = []
+
+    for line in content.splitlines():
+        _tmp.append(s2t(line))
+
+    return "\n".join(_tmp)
+
+def s2t(text):
+    return converter.convert(text)
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Convert simplified chinese to traditional chinese in epub.")
+    parser.add_argument('file', nargs='+', help="epub files")
+    args = parser.parse_args()
+
+    if len(args.file) == 1 and "*" in args.file[0]:
+        fn_list = glob.glob(args.file[0])
+    else:
+        fn_list = args.file
+
+    for fn in fn_list:
+        if not Path(fn).suffix == ".epub":
+            print(f"Skipping file {fn}, which is not an epub document.")
+        elif fn == s2t(fn):
+            print(f"Skipping file {fn}, which has already been converted.")
+        else:
+            t = time.time()
+            print(f"Converting {fn}")
+            buffer = BytesIO()
+            output = convert_epub(fn, buffer)
+            with open(s2t(fn), "wb") as f:
+                f.write(buffer.getvalue())
+            print(f"File {fn} is successfully converted. Time elapsed: {round(time.time() - t, 2)}s")

static/main.css

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+body, html {
+    height: 100%;
+    width: 100%;
+    margin: 0;
+    padding: 0;
+}
+
+body, #main {
+    display: flex;
+    flex-direction: column;
+}
+
+.close.button {
+    position: absolute;
+    z-index: 3;
+    right: 2em;
+    top: 2em;
+}
+
+#dragzone[data-mode="selecting"] .close.button,
+#dragzone:not([data-mode="selected"]) #submitbtn,
+#dragzone:not([data-mode="converted"]) #downloadbtn,
+#dragzone:not([data-mode^="upload"]) .ts.progress {
+    display: none;
+}
+
+#main {
+    flex: 1;
+    flex-grow: 1;
+    justify-content: center;
+}
+
+#dragzone {
+    margin-bottom: 1em;
+}
+
+#progressbar .bar {
+    min-width: 0;
+}
+
+#upload {
+    visibility: hidden;
+    height: 0;
+    width: 0;
+    position: absolute;
+    top: 0;
+    left: 0;
+}
+
+#submit {
+    z-index: 5;
+}

static/upload.js

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+const CancelToken = axios.CancelToken;
+let cancel;
+
+const dqs = (selector, ctx = document) => {
+    return ctx.querySelector(selector);
+}
+
+HTMLElement.prototype.on = function(event, callback) {
+    this.addEventListener(event, callback);
+    return this;
+}
+
+function updateFile(files) {
+    let filename = files[0].name;
+    let size = files[0].size;
+
+    // check file extension
+    if (filename.split(".").pop() != "epub") {
+        ts(".ts.snackbar").snackbar({
+            content: "只接受 EPUB 格式的檔案!"
+        });
+        return false;
+    }
+
+    // check file size
+    if (size >= sizeLimit) {
+        ts(".ts.snackbar").snackbar({
+            content: "檔案過大!"
+        });
+        return false;
+    }
+
+    if (!dqs("#upload").files.length) {
+        dqs("#upload").files = files;
+    }
+
+    dqs(".header", dqs("#dragzone")).textContent = filename;
+    dqs(".description", dqs("#dragzone")).textContent = `檔案大小: ${humanFileSize(size, false)}`;
+    dqs("#dragzone").dataset.mode = "selected";
+}
+
+function reset(ev) {
+    if (ev) {
+        ev.preventDefault();
+        ev.stopPropagation();
+    }
+    dqs(".header", dqs("#dragzone")).textContent = "上傳";
+    dqs(".description", dqs("#dragzone")).innerHTML = "將檔案拖拉至此處進行上傳，或是點擊此處選取檔案。<br>Max upload size : " + humanFileSize(sizeLimit, false);
+    dqs("#dragzone").dataset.mode = "selecting";
+    dqs("#upload").value = "";
+}
+
+// https://stackoverflow.com/a/14919494
+function humanFileSize(bytes, si) {
+    var thresh = si ? 1000 : 1024;
+    if(Math.abs(bytes) < thresh) {
+        return bytes + ' B';
+    }
+    var units = si
+        ? ['kB','MB','GB','TB','PB','EB','ZB','YB']
+        : ['KiB','MiB','GiB','TiB','PiB','EiB','ZiB','YiB'];
+    var u = -1;
+    do {
+        bytes /= thresh;
+        ++u;
+    } while (Math.abs(bytes) >= thresh && u < units.length - 1);
+    return bytes.toFixed(1)+' '+units[u];
+}
+
+dqs("#upload").on("change", ev => {
+    let el = ev.target;
+    if (el.files.length) {
+        if (el.files.length > 1) {
+            ts('.snackbar').snackbar({
+                content: "一次僅可上傳一個檔案。"
+            });
+        } else {
+            updateFile(el.files);
+        }
+    } else {
+        reset();
+    }
+});
+
+dqs(".ts.close.button").on("click", ev => {
+    if (dqs("#dragzone").dataset.mode == "uploading") {
+        if (cancel) {
+            cancel();
+        }
+    }
+    reset();
+});
+
+dqs("#submitbtn").on("click", ev => {
+    ev.stopPropagation();
+    ev.preventDefault();
+
+    dqs("#dragzone").dataset.mode = "uploading";
+
+    // clean up styles
+    ["preparing", "positive", "negative"].forEach(c => {
+        dqs("#progressbar").classList.toggle(c, false);
+    });
+
+    dqs("#progressbar .bar").style.width = "0";
+    if (dqs("#downloadbtn").href) {
+        window.URL.revokeObjectURL(dqs("#downloadbtn").href);
+        dqs("#downloadbtn").href = "";
+        dqs("#downloadbtn").removeAttribute("download");
+    }
+
+    axios.post("./api/convert", new FormData(document.form), {
+        responseType: "blob",
+        cancelToken: new CancelToken(function (executor) {
+            cancel = executor;
+        }),
+        onUploadProgress: (ev) => {
+            percentage = (ev.loaded / ev.total) * 100
+            dqs("#progressbar .bar").style.width = percentage + "%";
+            if (percentage == 100) {
+                dqs("#progressbar").classList.add("preparing");
+            }
+        }
+    }).then(function (res) {
+        dqs("#dragzone").dataset.mode = "converted";
+        dqs("#progressbar").classList.remove("preparing");
+
+        let blob = new Blob([res.data], { type: "application/epub+zip" });
+        let disposition = res.headers['content-disposition'];
+        let filename = disposition.slice(disposition.lastIndexOf("=") + 1, disposition.length);
+        if (filename.startsWith("UTF-8''")) {
+            filename = decodeURIComponent(filename.slice(7, filename.length));
+        }
+        dqs("#downloadbtn").href = window.URL.createObjectURL(blob); 
+        dqs("#downloadbtn").setAttribute("download", filename);
+    }).catch(function (e) {
+        dqs("#dragzone").dataset.mode = "uploadend";
+        dqs("#progressbar").classList.remove("preparing");
+        dqs("#progressbar").classList.add("negative");
+        if (e.response) {
+            if (e.response.data instanceof Blob && e.response.data.type == "application/json") {
+                let reader = new FileReader();
+                reader.onload = function () {
+                    let data = JSON.parse(this.result);
+                    ts(".snackbar").snackbar({
+                        content: `錯誤: ${data.error}`
+                    });
+                }
+                reader.readAsText(e.response.data);
+            }
+        } else if (axios.isCancel(e)) {
+            console.log("Upload progress canceled");
+            dqs("#progressbar").classList.remove("negative");
+            ts(".snackbar").snackbar({
+                content: "上傳已取消"
+            });
+        } else {
+            console.error(e);
+        }
+    });
+});
+
+dqs("#dragzone").on("click", ev => {
+    ev.preventDefault();
+
+    if (dqs("#dragzone").dataset.mode != "uploading") {
+        let allowlist = ["button", "a"];
+        if (allowlist.indexOf(ev.target.tagName.toLowerCase()) == -1) {
+            dqs("#upload").click();
+        }
+    }
+});
+
+dqs("#downloadbtn").on("click", ev => {
+    ev.preventDefault();
+    let el = ev.target;
+
+    let link = document.createElement("a");
+    link.setAttribute("download", el.getAttribute("download"));
+    link.style.display = "none";
+    link.href = el.href;
+    document.body.appendChild(link);
+    link.click();
+    document.body.removeChild(link);
+
+    reset();
+});
+
+dqs("#dragzone").on("drop", ev => {
+    ev.stopPropagation();
+    ev.preventDefault();
+
+    if (dqs("#dragzone").dataset.mode != "uploading") {
+        let files = ev.dataTransfer.files;
+        if (files) {
+            if (files.length > 1) {
+                ts('.snackbar').snackbar({
+                    content: "一次僅可上傳一個檔案。"
+                });
+            } else if (files.length == 1) {
+                updateFile(files);
+            }
+        }
+    }
+});
+
+["dragenter", "dragover"].forEach(event => {
+    dqs("#dragzone").on(event, ev => {
+        ev.stopPropagation();
+        ev.preventDefault();
+    });
+});

templates/index.html.j2

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+<!DOCTYPE html>
+<html>
+    <head>
+        <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+        <meta charset="utf-8">
+        <!-- Tocas UI：CSS 與元件 -->
+        <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/tocas-ui/2.3.3/tocas.css">
+        <!-- Tocas JS：模塊與 JavaScript 函式 -->
+        <script src="https://cdnjs.cloudflare.com/ajax/libs/tocas-ui/2.3.3/tocas.js"></script>
+        <link rel="stylesheet" href="{{ url_for('static', filename='main.css') }}">
+    </head>
+    <title>EPUB Convert</title>
+    <body>
+        <form action="/api/convert" method="post" enctype="multipart/form-data" name="form" id="form">
+            <input type="file" name="upload" id="upload" accept=".epub" />
+        </form>
+        <div class="ts center aligned big header">
+            EPUB Convert
+        </div>
+        <div class="ts container" id="main">
+            <div class="ts basic padded dashed clickable slate" id="dragzone" data-mode="selecting">
+                <button class="ts close button"></button>
+                <i class="upload symbol icon"></i>
+                <span class="header">上傳</span>
+                <span class="description">將檔案拖拉至此處進行上傳，或是點擊此處選取檔案。<br>Max upload size : {{ limit_human_readable }}</span>
+                <div class="action">
+                    <button class="ts primary button" id="submitbtn">Upload</button>
+                    <a class="ts positive button" id="downloadbtn">Download</a>
+                    <div class="ts progress" id="progressbar">
+                        <div class="bar"></div>
+                    </div>
+                </div>
+            </div>
+        </div>
+        <footer class="ts padded attached center aligned inverted segment">
+            <p>Convert simplified chinese to traditional chinese in epub.</p>
+            <p>&copy; Stone App | <a href="https://github.com/stoneapptech/epub_convert">GitHub Repo</a></p>
+        </footer>
+        <!-- snackbar -->
+        <div class="ts top right snackbar">
+            <div class="content"></div>
+        </div>
+
+        <script src="https://cdnjs.cloudflare.com/ajax/libs/axios/0.19.2/axios.min.js"></script>
+        <script>
+            const sizeLimit = {{ limit }};
+        </script>
+        <script src="{{ url_for('static', filename='upload.js') }}"></script>
+    </body>
+</html>

web.py

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+import tempfile
+import hashlib
+from io import BytesIO
+from flask import (
+    Flask, jsonify, redirect, request, render_template, send_file, url_for, safe_join
+)
+from werkzeug.utils import secure_filename
+from convert import convert_epub, s2t
+from pathlib import Path
+
+app = Flask(__name__)
+app.config['JSON_AS_ASCII'] = False
+app.config['MAX_CONTENT_LENGTH'] = 20 * 1024 * 1024
+
+def human_file_size(bytes_count):
+    threshold = 1024
+    units = ['KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB']
+    if bytes_count < threshold:
+        return f"{bytes_count} B"
+
+    ui = -1
+    while True:
+        bytes_count /= threshold
+        ui += 1
+        if bytes_count < threshold or ui == (len(units) - 1):
+            break
+
+    return f"{round(bytes_count, 1)} {units[ui]}"
+
+@app.route("/", methods=["GET"])
+def render_index():
+    limit = app.config["MAX_CONTENT_LENGTH"]
+    return render_template("index.html.j2", limit=limit, limit_human_readable=human_file_size(limit))
+
+@app.route('/api/convert', methods=["POST"])
+def upload_epub_sync():
+    if 'upload' not in request.files:
+        return jsonify({"status": False, "error": "No file is specified."}), 400
+
+    epub_file = request.files['upload']
+
+    if epub_file.filename == '':
+        return jsonify({"status": False, "error": "No file name."}), 400
+
+    # https://stackoverflow.com/questions/283707/size-of-an-open-file-object/283719#283719
+    epub_file.seek(0, 2)
+    end_position = epub_file.tell()
+    if end_position > app.config['MAX_CONTENT_LENGTH']:
+        return jsonify({"status": False, "error": f"File is too large. Maxium file size is {human_file_size(app.config['MAX_CONTENT_LENGTH'])}"}), 413
+
+    if epub_file and Path(epub_file.filename).suffix == ".epub":
+        output_buffer = BytesIO()
+        try:
+            _result = convert_epub(epub_file, output_buffer)
+            print(f"Converted Successfully. File: {s2t(epub_file.filename)}")
+            output_buffer.seek(0)
+            return send_file(output_buffer, as_attachment=True, attachment_filename=s2t(epub_file.filename))
+        except Exception as e:
+            error_class = e.__class__.__name__
+            return jsonify({"status": False, "error": error_class}), 500
+    else:
+        return jsonify({"status": False, "error": "Not an epub document"}), 415 # Unsupported Media Type
+
+if __name__ == "__main__":
+    app.run(host="0.0.0.0", debug=True)

web.wsgi

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+from web import app as application