.Net6中想实现对某个网址截屏，可通过Selenium模拟访问网址并实现截图。
实现
安装Nuget包：
<PackageReference Include="Selenium.Chrome.WebDriver" Version="85.0.0" />
<PackageReference Include="Selenium.Support" Version="4.1.0" />
<PackageReference Include="Selenium.WebDriver" Version="4.1.0" />
之后可通过代码实现模拟访问网址并截图：
public static string PageScreenshot(string url, string uploadbasepath)
{
ChromeDriver driver = null;
try
{
ChromeOptions options = new ChromeOptions();
options.AddArguments("headless", "disable-gpu", "no-sandbox");
driver = new ChromeDriver(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), options);
//driver = new ChromeDriver("/usr/bin/google-chrome-stable", options);
driver.Navigate().GoToUrl(url);
string width = driver.ExecuteScript("return document.body.scrollWidth").ToString();
string height = driver.ExecuteScript("return document.body.scrollHeight").ToString();
driver.Manage().Window.Size = new System.Drawing.Size(int.Parse(width), int.Parse(height)); //=int.Parse( height);
var screenshot = (driver as ITakesScreenshot).GetScreenshot();
//directory create
var basepath = uploadbasepath + DateTime.Now.ToString("yyyyMMdd") + "/";
if (!Directory.Exists(uploadbasepath))
{
Directory.CreateDirectory(uploadbasepath);
}
if (!Directory.Exists(basepath))
{
Directory.CreateDirectory(basepath);
}
var path = basepath + Guid.NewGuid().ToString("N") + ".jpg";
screenshot.SaveAsFile(path);
return path;
}
catch (Exception ex)
{
throw;
}
finally
{
if (driver != null)
{
driver.Close();
driver.Quit();
}
}
}
需要另外做的一步是把chromedriver从bin/Release/netcoreapp3.1/chromedriver复制到publish目录。
你以为到这就完了？这个代码确实可以在windows/linux非容器环境下运行。但是在docker里还是有些不一样。
Docker中运行的那些坑
首先需要注意.netcore3.1在Docker中操作图片记得安装libgdiplus.so
#Dockerfile
RUN apt-get update -y && apt-get install -y --allow-unauthenticated libgdiplus && apt-get clean && ln -s /usr/lib/libgdiplus.so /usr/lib/gdiplus.dll
1.第一个坑
首先遇到的就是OpenQA.Selenium.DriverServiceNotFoundException异常，异常信息是。
OpenQA.Selenium.DriverServiceNotFoundException: The file /opt/google/chrome/chrome/chromedriver does not exist. The driver can be downloaded at http://chromedriver.storage.googleapis.com/index.html
这个异常明显是找不到chromedriver，那就与在非Docker环境linux中直接运行的方式一样，尝试把chromedriver复制到Docker的publish目录中，在Dockerfile中添加以下内容。
#dockerfile
RUN cp /src/xxx/Release/netcoreapp3.1/chromedriver /app/publish/
2.第二个坑
尝试运行以上容器，还是失败，进入容器内部，直接运行chromedriver，可以看到缺少libxx.so之类的库。那咋办，只能尝试在镜像中安装chrome，这样相关库就有了。
安装chrome相关资料
https://stackoverflow.com/questions/55206172/how-to-run-dotnet-core-app-with-selenium-in-docker
https://github.com/devpabloassis/seleniumdotnetcore/blob/master/Dockerfile
那在Dockerfile中添加安装chrome的命令。
#Dockerfile Install Chrome
RUN apt-get update && apt-get install -y \
apt-transport-https \
ca-certificates \
curl \
gnupg \
hicolor-icon-theme \
libcanberra-gtk* \
libgl1-mesa-dri \
libgl1-mesa-glx \
libpango1.0-0 \
libpulse0 \
libv4l-0 \
fonts-symbola \
--no-install-recommends \
&& curl -sSL https://dl.google.com/linux/linux_signing_key.pub | apt-key add - \
&& echo "deb [arch=amd64] https://dl.google.com/linux/chrome/deb/ stable main" > /etc/apt/sources.list.d/google.list \
&& apt-get update && apt-get install -y \
google-chrome-stable \
--no-install-recommends \
&& apt-get purge --auto-remove -y curl \
&& rm -rf /var/lib/apt/lists/*
3.第三个坑
运行以上修改后的容器，又一个异常。
DevToolsActivePort file doesn't exist
继续查资料发现需要加个参数disable-dev-shm-usage
https://stackoverflow.com/questions/50642308/webdriverexception-unknown-error-devtoolsactiveport-file-doesnt-exist-while-t
但是前面试了不在docker内运行，需要这个参数，那就加个环境变量区分开docker与非docker环境。
#Dockerfile
ENV INDOCKER 1
public static string PageScreenshot(string url, string uploadbasepath)
{
ChromeDriver driver = null;
try
{
var indocker = Environment.GetEnvironmentVariable("INDOCKER");
ChromeOptions options = new ChromeOptions();
if (indocker == "1")
{
options.AddArguments("headless", "disable-gpu", "no-sandbox", "disable-dev-shm-usage");
//driver = new ChromeDriver("/opt/google/chrome/chrome", options);
}
else
{
options.AddArguments("headless", "disable-gpu", "no-sandbox");
}
driver = new ChromeDriver(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), options);
//driver = new ChromeDriver("/usr/bin/google-chrome-stable", options);
driver.Navigate().GoToUrl(url);
string width = driver.ExecuteScript("return document.body.scrollWidth").ToString();
string height = driver.ExecuteScript("return document.body.scrollHeight").ToString();
driver.Manage().Window.Size = new System.Drawing.Size(int.Parse(width), int.Parse(height)); //=int.Parse( height);
var screenshot = (driver as ITakesScreenshot).GetScreenshot();
//directory create
var basepath = uploadbasepath + DateTime.Now.ToString("yyyyMMdd") + "/";
if (!Directory.Exists(uploadbasepath))
{
Directory.CreateDirectory(uploadbasepath);
}
if (!Directory.Exists(basepath))
{
Directory.CreateDirectory(basepath);
}
var path = basepath + Guid.NewGuid().ToString("N") + ".jpg";
screenshot.SaveAsFile(path);
return path;
}
catch (Exception ex)
{
throw;
}
finally
{
if (driver != null)
{
driver.Close();
driver.Quit();
}
}
}
4.第四个坑
尝试运行上面修改后的容器，又一个异常。
This version of ChromeDriver only supports Chrome version 99
Current browser version is 109.0.5414.74 with binary path /usr/bin/google-chrome
这个信息字面意思就是之前第一个坑复制的chromedriver版本较低。那就直接去官网下载最新的chromedriver，并放到镜像内。
下载地址：http://chromedriver.storage.googleapis.com/index.html
# Dockerfile
COPY ["xxx/chromedriver", "."]
RUN chmod +x chromedriver
5.第五个坑
继续尝试运行，发现这次能成功截图了，等等...这字体咋还是乱码呢。
明显是中文乱码了，应该是容器内没中文字体，那就安装中文字体，字体可以从C:\Windows\Fonts中获取ttc,ttf字体文件。
#Dockerfile
RUN apt-get update
RUN apt-get install -y --no-install-recommends libgdiplus libc6-dev
RUN apt-get install -y fontconfig xfonts-utils
COPY fonts/ /usr/share/fonts/
RUN mkfontscale
RUN mkfontdir
RUN fc-cache -fv
再次运行，终于成功：
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