专题3:编写你自己的PDF编辑器, 实现PDF页面提取, 页面合并与替换

专题六:PDF页面提取, 页面合并与替换

• • • 项目介绍
    • 需要模块
    • 项目创建
    • 设计URL
    • Form表单信息
    • 视图函数
    • 模板页面

专题五:python操作文件(txt,csv,word,pdf,图片等)，这篇博客已经介绍了基本的文件操作，本篇主要介绍pdf的操作，结合django做成一个实际的案例。

项目介绍

我们的开发思路是这样子的。我们设计一个表单，让用户上传PDF文件和输入提取页面号码。服务器在收到PDF文件后使用PyPDF2读取用户上传的PDF文件，提取我们所需要的页面，然后通过HttpResponse将这个新生成的PDF文件通过浏览器返回给客户。
页面提取
页面合并
页面替换

需要模块

PyPDF2
django

项目创建

django-admin startproject mysite
python manage.py startapp pdf

设计URL

# mysite/urls.py
urlpatterns = [path('admin/', admin.site.urls),path('pdf/',include('pdf.urls'))
]

# pdf/urls.py
from django.urls import path
from . import viewsapp_name = 'pdf'urlpatterns = [# 上传pdf，用户输入需要提取的页面, 返回需要提取的页面# 提取单页path('extract/single/', views.pdf_single_page_extract, name='pdf_single_page_extract'),# 提取范围内页面path('extract/range/', views.pdf_range_extract, name='pdf_range_extract'),# pdf合并path('merge/', views.pdf_merge, name='pdf_merge'),# 页面替换path('replace/', views.pdf_replace, name='pdf_replace'),
]

Form表单信息

#pdf/forms.pyfrom django import formsclass PdfExtractForm(forms.Form):file = forms.FileField(label="Upload PDF Document")page = forms.CharField(max_length=20, label="Page Number")def clean_file(self):file = self.cleaned_data.get('file')if not file.name.lower().endswith('.pdf'):raise forms.ValidationError("Only pdf documents are allowed. ")return fileclass PdfMergeForm(forms.Form):file1 = forms.FileField(label="PDF file 1")file2 = forms.FileField(label="PDF file 2", required=False)file3 = forms.FileField(label="PDF file 3", required=False)file4 = forms.FileField(label="PDF file 4", required=False)file5 = forms.FileField(label="PDF file 5", required=False)class PdfReplaceForm(forms.Form):file1 = forms.FileField(label="Replacement page")file2 = forms.FileField(label="PDF document to be replaced")page = forms.IntegerField(label="Replace page number")

视图函数

#包

import os
import zipfileimport PyPDF2
from django.http import FileResponse
from django.shortcuts import renderfrom pdf.forms import PdfExtractForm, PdfMergeForm, PdfReplaceForm

def pdf_single_page_extract(request):if request.method == 'POST':form = PdfExtractForm(request.POST, request.FILES)if form.is_valid():f = form.cleaned_data['file']# 转化为pdf对象pdfFileObj = PyPDF2.PdfFileReader(f)# 获取需要提取的页面参数page_num_info = form.cleaned_data['page'].strip()print(page_num_info)if len(page_num_info) == 2:page_num_list = page_num_info.split(',')[0]print('page_num_list', page_num_list)else:page_num_list = page_num_info.split(',')print(page_num_list)# 创建压缩文件对象 生成提取文件压缩包zf = zipfile.ZipFile(os.path.join('media', 'extracted_pages.zip'), 'w')for page_num in page_num_list:# pdf文档页面对象编码是从0开始 所以减一page_index = int(page_num) - 1# 利用PyPDF2提取页面对象pageObj = pdfFileObj.getPage(page_index)# 利用PyPDF2创建新的PDF WriterpdfWriter = PyPDF2.PdfFileWriter()pdfWriter.addPage(pageObj)# pdf文件路径pdf_file_path = os.path.join('media', 'extracted_page_{}.pdf'.format(page_num))# 将提取页面写入新的PDF文件with open(pdf_file_path, 'wb') as pdfOutputFile:pdfWriter.write(pdfOutputFile)zf.write(pdf_file_path)zf.close()response = FileResponse(open(os.path.join('media', 'extracted_pages.zip'), 'rb'))response['content_type'] = "application/zip"response['Content-Disposition'] = 'attachment; filename="extracted_pages.zip"'return responseelse:form = PdfExtractForm()return render(request, 'pdf/pdf_extract.html', {'form': form})def pdf_range_extract(request):if request.method == 'POST':# 如果用户通过POST提交form = PdfExtractForm(request.POST, request.FILES)if form.is_valid():# 获取上传的文件f = form.cleaned_data['file']# 转化为PDF文件对象pdfFileObj = PyPDF2.PdfFileReader(f)page_range = form.cleaned_data['page'].strip().split('-')page_start = int(page_range[0].strip())page_end = int(page_range[1].strip())# Extracted pdf file pathpdf_file_path = os.path.join('media', 'extracted_page_{}-{}.pdf'.format(page_start, page_end))pdfOutputFile = open(pdf_file_path, 'ab+')# 利用PyPDF2创建新的Pdf WriterpdfWriter = PyPDF2.PdfFileWriter()for page_num in range(page_start, page_end + 1):# pdf文档页码对象编码是从0开始，所以减一page_index = int(page_num) - 1# 利用PyPDF2提取页码对象pageObj = pdfFileObj.getPage(page_index)  # 从0编码# 添加已读取的页面对象pdfWriter.addPage(pageObj)pdfWriter.write(pdfOutputFile)pdfOutputFile.close()extractedPage = open(pdf_file_path, 'rb')response = FileResponse(extractedPage)response['content_type'] = "application/octet-stream"response['Content-Disposition'] = 'attachment; filename="extracted_pages.pdf"'return responseelse:# 如果用户没有通过POST，提交生成空表单form = PdfExtractForm()return render(request, 'pdf/pdf_range_extract.html', {'form': form})def pdf_merge(request):if request.method == 'POST':# 如果用户通过POST提交form = PdfMergeForm(request.POST, request.FILES)if form.is_valid():# 获取上传的文件1f1 = form.cleaned_data['file1']# 获取上传的文件2f2 = form.cleaned_data['file2']# 获取上传的文件3f3 = form.cleaned_data['file3']# 获取上传的文件4f4 = form.cleaned_data['file4']# 获取上传的文件5f5 = form.cleaned_data['file5']f_list = [f1, f2, f3, f4, f5]# 创建PDF文件合并对象，添加合并文件pdfMerger = PyPDF2.PdfFileMerger()# 转化为PDF文件对象for f in f_list:if f:pdfFileObj = PyPDF2.PdfFileReader(f)pdfMerger.append(pdfFileObj)# 将合并文件对象写入到merged_file.pdfwith open(os.path.join('media', 'merged_file.pdf'), 'wb') as pdfOutputFile:pdfMerger.write(pdfOutputFile)# 打开合并的merged_file.pdf，通过FileResponse输出response = FileResponse(open(os.path.join('media', 'merged_file.pdf'), 'rb'))response['content_type'] = "application/octet-stream"response['Content-Disposition'] = 'attachment; filename="merged_file.pdf"'return responseelse:# 如果通过POST提交，但表单未通过验证form = PdfMergeForm()else:# 如果用户没有通过POST，提交生成空表单form = PdfMergeForm()return render(request, 'pdf/pdf_merge.html', {'form': form})def pdf_replace(request):if request.method == 'POST':# 如果用户通过POST提交form = PdfReplaceForm(request.POST, request.FILES)if form.is_valid():# 获取需要插入的PDF页面文件1f1 = form.cleaned_data['file1']# 获取需要被替换的文件2f2 = form.cleaned_data['file2']# 获取替换页码数page = form.cleaned_data['page']# 获取文件2总页数pdfFileObj = PyPDF2.PdfFileReader(f2)total_page = pdfFileObj.getNumPages()# 获取文件2第一部分-人为可读页码page_start = 1page_end = page - 1pdfOutputFile1 = open(os.path.join('media', 'part_1.pdf'), 'wb+')# 利用PyPDF2创建新的Pdf WriterpdfWriter = PyPDF2.PdfFileWriter()for page_num in range(page_start, page_end + 1):# pdf文档页码对象编码是从0开始，所以减一page_index = int(page_num) - 1# 利用PyPDF2提取页码对象pageObj = pdfFileObj.getPage(page_index)  # 从0编码# 添加已读取的页面对象pdfWriter.addPage(pageObj)pdfWriter.write(pdfOutputFile1)pdfOutputFile1.close()# 获取文件2第2部分-人为可读页码page_start = page + 1page_end = total_pagepdfOutputFile2 = open(os.path.join('media', 'part_2.pdf'), 'wb+')# 利用PyPDF2创建新的Pdf WriterpdfWriter = PyPDF2.PdfFileWriter()for page_num in range(page_start, page_end + 1):# pdf文档页码对象编码是从0开始，所以减一page_index = int(page_num) - 1# 利用PyPDF2提取页码对象pageObj = pdfFileObj.getPage(page_index)  # 从0编码# 添加已读取的页面对象pdfWriter.addPage(pageObj)pdfWriter.write(pdfOutputFile2)pdfOutputFile2.close()f2_part_1 = open(os.path.join('media', 'part_1.pdf'), 'rb+')f2_part_2 = open(os.path.join('media', 'part_2.pdf'), 'rb+')# 创建PDF文件合并对象，添加合并文件pdfMerger = PyPDF2.PdfFileMerger()pdfMerger.append(PyPDF2.PdfFileReader(f2_part_1))pdfMerger.append(PyPDF2.PdfFileReader(f1))pdfMerger.append(PyPDF2.PdfFileReader(f2_part_2))# 将合并文件对象写入到replaced_file.pdfwith open(os.path.join('media', 'replaced_file.pdf'), 'wb') as pdfOutputFile:pdfMerger.write(pdfOutputFile)# 打开合并的replaced_file.pdf，通过HttpResponse输出response = FileResponse(open(os.path.join('media', 'replaced_file.pdf'), 'rb'))response['content_type'] = "application/octet-stream"response['Content-Disposition'] = 'attachment; filename="replaced_file.pdf"'return responseelse:# 如果通过POST提交，但表单未通过验证form = PdfReplaceForm()else:# 如果用户没有通过POST，提交生成空表单form = PdfReplaceForm()return render(request, 'pdf/pdf_replace.html', {'form': form})

模板页面

#base.html

{% load static %}<html lang="en">
<head>
<title>{% block title %}Django PDF提取, 合并与替换{% endblock %} </title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
</head><body><!-- Page content of course! -->
<main><div class="container">{% block content %}{% if error_message %}<p><strong>{{ error_message}}</strong></p>{% endif %}{% endblock %}</div>
</main><footer class="footer">{% block footer %}{% endblock %}
</footer>
<!--End of Footer--><!-- Bootstrap core JavaScript
================================================== --><script src="https://code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script></body>
</html>

#pdf_extract.html

{% extends "pdf/base.html" %}{% block content %}<p><a href="{% url 'pdf:pdf_single_page_extract' %}">PDF Singe Page Extract(单页提取)</a>|<a href="{% url 'pdf:pdf_range_extract' %}">PDF Page Range Extract(页面范围提取)</a> |<a href="{% url 'pdf:pdf_merge' %}">PDF Merge(合并)</a> |<a href="{% url 'pdf:pdf_replace' %}">PDF Replace(替换)</a></p><h3>PDF Single Page Extract (单页提取)</h3><p>输入页面号码，如1或者3,5,9。 Enter page numbers such as 1, or 1, 3, 5.</p>{{ form.non_field_errors }}<form method="post" enctype="multipart/form-data" action="">{% csrf_token %}{{ form.as_p }}<button type="submit" class="btn btn-primary">Extract</button></form>{% endblock %}

#pdf_range_extract.html

{% extends "pdf/base.html" %}{% block content %}<p><a href="{% url 'pdf:pdf_single_page_extract' %}">PDF Singe Page Extract(单页提取)</a>|<a href="{% url 'pdf:pdf_range_extract' %}">PDF Page Range Extract(页面范围提取)</a> |<a href="{% url 'pdf:pdf_merge' %}">PDF Merge(合并)</a> |<a href="{% url 'pdf:pdf_replace' %}">PDF Replace(替换)</a></p><h3>PDF Page Range Extract (页面范围提取)</h3><p>请输入页面范围, 如2-8, 3-10。Please enter page range such as 2-8, 3-10.</p>{{ form.non_field_errors }}<form method="post" enctype="multipart/form-data" action="">{% csrf_token %}{{ form.as_p }}<button type="submit" class="btn btn-primary">Extract</button></form>{% endblock %}

#pdf_merge.html

{% extends "pdf/base.html" %}{% block content %}<p><a href="{% url 'pdf:pdf_single_page_extract' %}">PDF Singe Page Extract(单页提取)</a>| <a href="{% url 'pdf:pdf_range_extract' %}">PDF Page Range Extract(页面范围提取)</a> |<a href="{% url 'pdf:pdf_merge' %}">PDF Merge(合并)</a> |<a href="{% url 'pdf:pdf_replace' %}">PDF Replace(替换)</a></p><h3>PDF Merge (合并) </h3><p>请按顺序上传PDF文件。Please upload pdf documents by order.</p><form method="post" enctype="multipart/form-data" action="">{% csrf_token %}{{ form.as_p }}<button type="submit" class="btn btn-primary">Merge</button></form>{% endblock %}

#pdf_replace.html

{% extends "pdf/base.html" %}{% block content %}
<p></p><a href="{% url 'pdf:pdf_single_page_extract' %}">PDF Singe Page Extract(单页提取)</a>
| <a href="{% url 'pdf:pdf_range_extract' %}">PDF Page Range Extract(页面范围提取)</a> | <a href="{% url 'pdf:pdf_merge' %}">PDF Merge(合并)</a> |
<a href="{% url 'pdf:pdf_replace' %}">PDF Replace(替换)</a></p><h3>PDF Replace(替换)</h3>
<p>一次仅能替换一个PDF页面。You can only replace 1 single page at a time.</p>
<form method="post" enctype="multipart/form-data" action="">{% csrf_token %}{{ form.as_p }}<button type="submit" class="btn btn-primary">Replace</button>
</form>{% endblock %}

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