A4格式的Selenium打印PDF
A4格式的Selenium打印PDF
提问于 2021-06-28 13:50:52
我有下面的代码打印成PDF (和它的工作)，我只使用谷歌Chrome打印。
def send_devtools(driver, command, params=None):
# pylint: disable=protected-access
if params is None:
params = {}
resource = "/session/%s/chromium/send_command_and_get_result" % driver.session_id
url = driver.command_executor._url + resource
body = json.dumps({"cmd": command, "params": params})
resp = driver.command_executor._request("POST", url, body)
return resp.get("value")
def export_pdf(driver):
command = "Page.printToPDF"
params = {"format": "A4"}
result = send_devtools(driver, command, params)
data = result.get("data")
return data如我们所见，我使用Page.printToPDF打印到base64，并在params paramenter上将"A4“作为format传递。
不幸的是，这个参数似乎被忽略了。我看到了一些使用木偶师的代码(格式化A4)，我认为这对我有帮助。
即使是硬编码的宽度和高度(见下面)，我也没有运气。
"paperWidth": 8.27, # inches
"paperHeight": 11.69, # inches使用上面的代码，是否可以将页面设置为A4格式？
Stack Overflow用户
回答已采纳
发布于 2021-07-12 20:27:50
最新员额07-17-2021
我决定使用Python包pdfminer.sixth验证我的原始代码的输出。
from pdfminer.pdfpage import PDFPage
from pdfminer.pdfpage import PDFParser
from pdfminer.pdfpage import PDFDocument
parser = PDFParser(open('test_1.pdf', 'rb'))
doc = PDFDocument(parser)
pageSizesList = []
for page in PDFPage.create_pages(doc):
print(page.mediabox)
# output
[0, 0, 612, 792]当我把这些点的尺寸转换成英寸时，我感到很震惊。其大小为8.5x11，不等于A4纸张的8.27x11.69。当我看到这个问题时，我决定通过查看铬和硒源代码来进一步探讨这个问题。
在铬源代码中，命令Page.printToPDF位于文件handler.cc中。
void PageHandler::PrintToPDF(Maybe<bool> landscape,
Maybe<bool> display_header_footer,
Maybe<bool> print_background,
Maybe<double> scale,
Maybe<double> paper_width,
Maybe<double> paper_height,
Maybe<double> margin_top,
Maybe<double> margin_bottom,
Maybe<double> margin_left,
Maybe<double> margin_right,
Maybe<String> page_ranges,
Maybe<bool> ignore_invalid_page_ranges,
Maybe<String> header_template,
Maybe<String> footer_template,
Maybe<bool> prefer_css_page_size,
Maybe<String> transfer_mode,
std::unique_ptr<PrintToPDFCallback> callback)该函数允许修改参数paper_width和paper_height。这些参数采用double. - C++双值是一种通用的数据类型，用于编译器内部定义和保存任何数值数据类型，特别是任何面向十进制的值。C++双数据类型既可以是小数，也可以是带值的整数。
这些参数具有默认值，这些默认值在铬DevTools协议中定义。
- paperWidth:纸张宽度(以英寸为单位)。默认为8.5英寸。
- paperHeight:纸的高度(以英寸为单位)。默认为11英寸
注意到chromium源代码和Chrome DevTools Protocol详细信息之间的参数格式之间的差异。
- paper_width在
chromium源代码中 - paperWidth中的
Chrome DevTools Protocol
根据chromium源代码，使用SendCommandAndGetResultWithTimeout.调用命令Page.printToPDF
Status WebViewImpl::PrintToPDF(const base::DictionaryValue& params,
std::string* pdf) {
// https://bugs.chromium.org/p/chromedriver/issues/detail?id=3517
if (!browser_info_->is_headless) {
return Status(kUnknownError,
"PrintToPDF is only supported in headless mode");
}
std::unique_ptr<base::DictionaryValue> result;
Timeout timeout(base::TimeDelta::FromSeconds(10));
Status status = client_->SendCommandAndGetResultWithTimeout(
"Page.printToPDF", params, &timeout, &result);
if (status.IsError()) {
if (status.code() == kUnknownError) {
return Status(kInvalidArgument, status);
}
return status;
}
if (!result->GetString("data", pdf))
return Status(kUnknownError, "expected string 'data' in response");
return Status(kOk);
}在我最初的回答中，我使用了send_command_and_get_result,，它类似于命令SendCommandAndGetResultWithTimeout.
# stub_devtools_client.h
Status SendCommandAndGetResult(
const std::string& method,
const base::DictionaryValue& params,
std::unique_ptr<base::DictionaryValue>* result) override;
Status SendCommandAndGetResultWithTimeout(
const std::string& method,
const base::DictionaryValue& params,
const Timeout* timeout,
std::unique_ptr<base::DictionaryValue>* result) override;在查看了硒源代码之后，还不清楚如何正确传递命令send_command_and_get_result或send_command_and_get_result_with_timeout.。
我在webdriver 硒源代码中注意到了这个函数：
def execute_cdp_cmd(self, cmd, cmd_args):
"""
Execute Chrome Devtools Protocol command and get returned result
The command and command args should follow chrome devtools protocol domains/commands, refer to link
https://chromedevtools.github.io/devtools-protocol/
:Args:
- cmd: A str, command name
- cmd_args: A dict, command args. empty dict {} if there is no command args
:Usage:
driver.execute_cdp_cmd('Network.getResponseBody', {'requestId': requestId})
:Returns:
A dict, empty dict {} if there is no result to return.
For example to getResponseBody:
{'base64Encoded': False, 'body': 'response body string'}
"""
return self.execute("executeCdpCommand", {'cmd': cmd, 'params': cmd_args})['value']在做了一些研究和测试之后，我发现这个函数可以用来实现您的用例。
import base64
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
from pdfminer.pdfpage import PDFPage
from pdfminer.pdfpage import PDFParser
from pdfminer.pdfpage import PDFDocument
chrome_options = Options()
chrome_options.add_argument("--disable-infobars")
chrome_options.add_argument("--disable-extensions")
chrome_options.add_argument("--disable-popup-blocking")
chrome_options.add_argument('--headless')
browser = webdriver.Chrome('/usr/local/bin/chromedriver', options=chrome_options)
browser.get('http://www.google.com')
# use can defined additional parameters if needed
params = {'landscape': False,
'paperWidth': 8.27,
'paperHeight': 11.69}
# call the function "execute_cdp_cmd" with the command "Page.printToPDF" with
# parameters defined above
data = browser.execute_cdp_cmd("Page.printToPDF", params)
# save the output to a file.
with open('file_name.pdf', 'wb') as file:
file.write(base64.b64decode(data['data']))
browser.quit()
# verify the page size of the PDF file created
parser = PDFParser(open('file_name.pdf', 'rb'))
doc = PDFDocument(parser)
pageSizesList = []
for page in PDFPage.create_pages(doc):
print(page.mediabox)
# output
[0, 0, 594.95996, 840.95996]输出以点数表示，需要转换为英寸。
- 594.95996点等于8.263332777783英寸
- 840.95996点等于11.6799994445英寸
8.263332777783 x 11.6799994445是A4纸的大小。
原职位07-13-2021
在调用函数参数时，可以传递多个Page.printToPDF.，其中两个参数是：
- paper_width
- paper_height
下面的代码将这些参数传递给Page.printToPDF.
import json
import base64
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
def send_devtools(driver, command, params=None):
if params is None:
params = {}
resource = "/session/%s/chromium/send_command_and_get_result" % driver.session_id
url = driver.command_executor._url + resource
body = json.dumps({"cmd": command, "params": params})
resp = driver.command_executor._request("POST", url, body)
return resp.get("value")
def create_pdf(driver, file_name):
command = "Page.printToPDF"
params = {'paper_width': '8.27', 'paper_height': '11.69'}
result = send_devtools(driver, command, params)
save_pdf(result, file_name)
return
def save_pdf(data, file_name):
with open(file_name, 'wb') as file:
file.write(base64.b64decode(data['data']))
print('PDF created')
chrome_options = Options()
chrome_options.add_argument("--disable-infobars")
chrome_options.add_argument("--disable-extensions")
chrome_options.add_argument("--disable-popup-blocking")
chrome_options.add_argument('--headless')
browser = webdriver.Chrome('/usr/local/bin/chromedriver', options=chrome_options)
browser.get('http://www.google.com')
create_pdf(browser, 'test_pdf_1.pdf')----------------------------------------
My system information
----------------------------------------
Platform: maxOS
OS Version: 10.15.7
Python Version: 3.9
Selenium: 3.141.0
pdfminer.sixth: 20201018
----------------------------------------页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/68164550
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