我尝试在谷歌云函数上将PDF转换为JPEG。我使用了Python模块pdf2image
。但是我不知道如何解决云函数上的No such file or directory: 'pdfinfo'
和"Unable to get page count. Is poppler installed and in PATH?
错误
错误代码与this question非常相似pdf2image是围绕poppler的“pdftoppm”和“pdftocairo”的包装。但我如何在谷歌云功能上安装poppler软件包,并将其添加到PATH?我找不到相关的参考资料。甚至有可能吗?如果没有,可以做什么
还有this question,但它没有用处
代码如下所示。入口点是process_image
import requests
from pdf2image import convert_from_path
def process_image(event, context):
# Download sample pdf file
url = 'https://www.adobe.com/support/products/enterprise/knowledgecenter/media/c4611_sample_explain.pdf'
r = requests.get(url, allow_redirects=True)
open('/tmp/sample.pdf', 'wb').write(r.content)
# Error occur on this line
pages = convert_from_path('/tmp/sample.pdf')
# Save pages to /tmp
for idx, page in enumerate(pages):
output_file_path = f"/tmp/{str(idx)}.jpg"
page.save(output_file_path, 'JPEG')
# To be saved to cloud storage
Requirement.txt:
requests==2.25.1
pdf2image==1.14.0
这是我得到的错误代码:
Traceback (most recent call last):
File "/layers/google.python.pip/pip/lib/python3.8/site-packages/pdf2image/pdf2image.py", line 441, in pdfinfo_from_path
proc = Popen(command, env=env, stdout=PIPE, stderr=PIPE)
File "/opt/python3.8/lib/python3.8/subprocess.py", line 858, in __init__
self._execute_child(args, executable, preexec_fn, close_fds,
File "/opt/python3.8/lib/python3.8/subprocess.py", line 1706, in _execute_child
raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'pdfinfo'
在处理上述异常期间,发生了另一个异常:
Traceback (most recent call last):
File "/layers/google.python.pip/pip/lib/python3.8/site-packages/flask/app.py", line 2447, in wsgi_app
response = self.full_dispatch_request()
File "/layers/google.python.pip/pip/lib/python3.8/site-packages/flask/app.py", line 1952, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/layers/google.python.pip/pip/lib/python3.8/site-packages/flask/app.py", line 1821, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/layers/google.python.pip/pip/lib/python3.8/site-packages/flask/_compat.py", line 39, in reraise
raise value
File "/layers/google.python.pip/pip/lib/python3.8/site-packages/flask/app.py", line 1950, in full_dispatch_request
rv = self.dispatch_request()
File "/layers/google.python.pip/pip/lib/python3.8/site-packages/flask/app.py", line 1936, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/layers/google.python.pip/pip/lib/python3.8/site-packages/functions_framework/__init__.py", line 149, in view_func
function(data, context)
File "/workspace/main.py", line 11, in process_image
pages = convert_from_path('/tmp/sample.pdf')
File "/layers/google.python.pip/pip/lib/python3.8/site-packages/pdf2image/pdf2image.py", line 97, in convert_from_path
page_count = pdfinfo_from_path(pdf_path, userpw, poppler_path=poppler_path)["Pages"]
File "/layers/google.python.pip/pip/lib/python3.8/site-packages/pdf2image/pdf2image.py", line 467, in pdfinfo_from_path
raise PDFInfoNotInstalledError(
pdf2image.exceptions.PDFInfoNotInstalledError: Unable to get page count. Is poppler installed and in PATH?
提前感谢您的帮助
云函数不支持安装定制的系统级软件包(即使它支持使用包管理器(如npm、pip)的相关编程语言的第三方库)。如https://cloud.google.com/functions/docs/reference/system-packages所示,没有包“poppler”
但是,您仍然可以使用其他预安装的软件包ghostscript可用于将pdf转换为图像
首先,您应该将pdf文件保存在云功能中(例如,从云存储)。您只能对/tmp进行磁盘写入访问 (https://cloud.google.com/functions/docs/concepts/exec#file_system)
将pdf转换为jpeg的终端命令示例如下
在python环境中使用该命令的示例代码:
注: 您可能希望改用imagemagick包,它本身使用ghostscript。但是,如Can't load PDF with Wand/ImageMagick in Google Cloud Function中所述,ImageMagick的PDF读取已被禁用,因为截至撰写本文时(2021-07-12),Ghostscript存在安全漏洞。提供的解决方案本质上是运行ghostscript的另一种方法
参考: https://www.the-swamp.info/blog/google-cloud-functions-system-packages/
出现此错误是因为poppler包在云函数中不工作,因为它需要将某些文件写入系统。不幸的是,您不能在诸如云函数之类的无服务器产品中写入文件系统
您可能想尝试方法,在另一个线程中描述,Cloud Functions for Firebase - Converting PDF to image,或者考虑使用GCP计算引擎来访问整个系统。
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