有没有我可以从谷歌搜索和下载随机图像的例子?使用随机搜索字符串?
我想将此图像用作隐写术图像,并且我希望它是随机图像。
我在 Visual Studio 2012 中使用 C#。
最佳答案
您可能不想要随机搜索字符串。您可能想要随机主题。这是一些可以帮助您的代码。首先,创建一个主题列表:
private readonly List<string> _topics = new List<string> {"dog", "car", "truck", "cat", "florida"};
当然,您可以随意更改、添加和删除任意数量的主题。接下来,我们将创建一个函数来从 Google 图片搜索中检索 HTML 代码,随机选择我们的主题之一进行搜索:
private string GetHtmlCode()
{
var rnd = new Random();
int topic = rnd.Next(0, _topics.Count - 1);
string url = "https://www.google.com/search?q=" + _topics[topic] + "&tbm=isch";
string data = "";
var request = (HttpWebRequest)WebRequest.Create(url);
var response = (HttpWebResponse)request.GetResponse();
using (Stream dataStream = response.GetResponseStream())
{
if (dataStream == null)
return "";
using (var sr = new StreamReader(dataStream))
{
data = sr.ReadToEnd();
}
}
return data;
}
一旦我们有了 HTML 代码,我们需要解析位于 images_table
表下的 img
标签,并将图像的 URL 存储在列表中:
private List<string> GetUrls(string html)
{
var urls = new List<string>();
int ndx = html.IndexOf("class=\"images_table\"", StringComparison.Ordinal);
ndx = html.IndexOf("<img", ndx, StringComparison.Ordinal);
while (ndx >= 0)
{
ndx = html.IndexOf("src=\"", ndx, StringComparison.Ordinal);
ndx = ndx + 5;
int ndx2 = html.IndexOf("\"", ndx, StringComparison.Ordinal);
string url = html.Substring(ndx, ndx2 - ndx);
urls.Add(url);
ndx = html.IndexOf("<img", ndx, StringComparison.Ordinal);
}
return urls;
}
我们需要的最后一个函数是获取一个 URL 并将图像字节下载到一个字节数组中:
private byte[] GetImage(string url)
{
var request = (HttpWebRequest)WebRequest.Create(url);
var response = (HttpWebResponse)request.GetResponse();
using (Stream dataStream = response.GetResponseStream())
{
if (dataStream == null)
return null;
using (var sr = new BinaryReader(dataStream))
{
byte[] bytes = sr.ReadBytes(100000);
return bytes;
}
}
return null;
}
最后,我们只需要将它们联系在一起:
string html = GetHtmlCode();
List<string> urls = GetUrls(html);
var rnd = new Random();
int randomUrl = rnd.Next(0, urls.Count - 1);
string luckyUrl = urls[randomUrl];
byte[] image = GetImage(luckyUrl);
using (var ms = new MemoryStream(image))
{
pictureBox1.Image = Image.FromStream(ms);
}
更新
我收到了一些关于这个答案的请求,要求我修改它以便它加载实际的全尺寸图像而不是缩略图。我已经修改了我的原始代码,以便它现在加载全尺寸图像而不是缩略图。
首先,像以前一样,创建一个主题列表:
private readonly List<string> _topics = new List<string> { "dog", "car", "truck", "cat", "florida" };
当然,您可以随意更改、添加和删除任意数量的主题。接下来我们将创建一个函数来从 Google 图像搜索中检索 HTML 代码,随机选择我们的主题之一进行搜索。这里的GetHtmlCode()
和缩略图版的GetHtmlCode()
不同,我们必须添加一个Accept
和一个UserAgent
添加到请求中,否则 Google 不会向我们提供完整尺寸的图片网址:
private string GetHtmlCode()
{
var rnd = new Random();
int topic = rnd.Next(0, _topics.Count - 1);
string url = "https://www.google.com/search?q=" + _topics[topic] + "&tbm=isch";
string data = "";
var request = (HttpWebRequest)WebRequest.Create(url);
request.Accept = "text/html, application/xhtml+xml, */*";
request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko";
var response = (HttpWebResponse)request.GetResponse();
using (Stream dataStream = response.GetResponseStream())
{
if (dataStream == null)
return "";
using (var sr = new StreamReader(dataStream))
{
data = sr.ReadToEnd();
}
}
return data;
}
GetUrls()
方法也被重写了,因为我们现在取回的 HTML 代码与我们在“缩略图”版本中取回的 HTML 代码不同。它仍然从 HTML 代码中解析出 URL:
private List<string> GetUrls(string html)
{
var urls = new List<string>();
int ndx = html.IndexOf("\"ou\"", StringComparison.Ordinal);
while (ndx >= 0)
{
ndx = html.IndexOf("\"", ndx + 4, StringComparison.Ordinal);
ndx++;
int ndx2 = html.IndexOf("\"", ndx, StringComparison.Ordinal);
string url = html.Substring(ndx, ndx2 - ndx);
urls.Add(url);
ndx = html.IndexOf("\"ou\"", ndx2, StringComparison.Ordinal);
}
return urls;
}
我们需要的最后一个函数是获取一个 URL 并将图像字节下载到一个字节数组中。此功能只有一处与“缩略图”版本不同的细微变化。我们必须更改 ReadBytes()
中的数字,因为我们的图像现在会更大:
private byte[] GetImage(string url)
{
var request = (HttpWebRequest)WebRequest.Create(url);
var response = (HttpWebResponse)request.GetResponse();
using (Stream dataStream = response.GetResponseStream())
{
if (dataStream == null)
return null;
using (var sr = new BinaryReader(dataStream))
{
byte[] bytes = sr.ReadBytes(100000000);
return bytes;
}
}
return null;
}
最后,我们只需要像以前一样将它们绑在一起:
string html = GetHtmlCode();
List<string> urls = GetUrls(html);
var rnd = new Random();
int randomUrl = rnd.Next(0, urls.Count - 1);
string luckyUrl = urls[randomUrl];
byte[] image = GetImage(luckyUrl);
using (var ms = new MemoryStream(image))
{
pictureBox1.Image = Image.FromStream(ms);
}
关于c# - 从 Google 选择并下载随机图片,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/27846337/