I am working on a cefsharp based browser and i am trying to implement a search engine into the browser, but the code I have tried docent work, it doesn't really have any errors but when i star the project and type something i the text field nothing happens and it dosent load the search engine i entered into the code, the only time the textbox loads anything is when a url is typed.
This is the code used in the browser that docent work
private void LoadUrl(string url)
{
if (Uri.IsWellFormedUriString(url, UriKind.RelativeOrAbsolute))
{
WebUI.Load(url);
}
else
{
var searchUrl = "https://www.google.com/search?q=" + WebUtility.HtmlEncode(url);
WebUI.Load(searchUrl);
}
}
i have also tried
void LoadURl(String url)
{
if (url.StartsWith("http"))
{
WebUI.Load(url);
}
else
{
WebUI.Load(url);
}
}
i was also suggested to try
private void LoadUrl(string url)
{
if (Uri.IsWellFormedUriString(url, UriKind.RelativeOrAbsolute))
{
WebUI.LoadUrl(url);
}
else
{
var searchUrl = "https://www.google.com/search?q=" + Uri.EscapeDataString(url);
WebUI.LoadUrl(searchUrl);
}
}
We have here really few Information on how your code works. But what I notice is that you use WebUtility.HtmlEncode for the search query. WebUtility has also a WebUtility.UrlEncode Method, that how I understand your question makes more sense it the context. This is the documentation for the method: https://learn.microsoft.com/de-de/dotnet/api/system.net.webutility.urlencode
The Url you are generating is invalid. You need to use Uri.EscapeDataString to convert the url param into a string that can be appended to a url.
// For this example we check if a well formed absolute Uri was provided
// and load that Url, all others will be loaded using the search engine
// e.g. https://github.com will load directly, attempting to load
// github.com will load the search engine with github.com as the query.
//
if (Uri.IsWellFormedUriString(url, UriKind.Absolute))
{
chromiumWebBrowser.LoadUrl(url);
}
else
{
var searchUrl = "https://www.google.com/search?q=" + Uri.EscapeDataString(url);
chromiumWebBrowser.LoadUrl(searchUrl);
}
nothing happens and it dosent load the search engine
You need to subscribe to the LoadError event to get actual error messages. It's up to you to display errors to the user. The following is a basic example:
chromiumWebBrowser.LoadError += OnChromiumWebBrowserLoadError;
private void OnChromiumWebBrowserLoadError(object sender, LoadErrorEventArgs e)
{
//Actions that trigger a download will raise an aborted error.
//Aborted is generally safe to ignore
if (e.ErrorCode == CefErrorCode.Aborted)
{
return;
}
var errorHtml = string.Format("<html><body><h2>Failed to load URL {0} with error {1} ({2}).</h2></body></html>",
e.FailedUrl, e.ErrorText, e.ErrorCode);
_ = e.Browser.SetMainFrameDocumentContentAsync(errorHtml);
}
For testing purposes you can also copy and paste the searchUrl string you've generated and try loading it in Chrome to see what happens, you should also get an error.
Im trying to update a string field in specific document using Firebase Firestore for my android app but every method I see is while knowing the document refernce which I find difficult to find in my program.
Would like for some help for another method or help in finding the document refernce using a specific field value.
Thanks in advance.
(using C# btw)
private async Task<string> GetDocRefAsync(string userId)
{
Object obj = await FirestoreData.GetFirestore().Collection(DBConstants.FS_COLLECTION_USERS).
WhereEqualTo(DBConstants.FS_COLLECTION_USERS_USER_ID, userId).Get();
QuerySnapshot snapshot = (QuerySnapshot)obj;
if (snapshot.IsEmpty)
{
Log.Debug("UpdateGroupAsync", "userId: " + userId + " not found");
return null;
}
string docRef = "";
foreach (DocumentSnapshot item in snapshot.Documents)
{
//docRef = item.;
}
return docRef;
}
Firstly ive tried to find the document ref using this code but dont have a function to get the ref even after getting the correct document.
the fourth line from the bottom is where I couldnt find it.
database pic
this.groupCode = code;
string strUserRef = GetDocRefAsync(userRef).ToString();
DocumentReference docReference = database.Collection(DBConstants.FS_COLLECTION_USERS_GROUPS_CODE).Document(strUserRef);
docReference.Update(DBConstants.FS_COLLECTION_USERS_GROUPS_CODE, groupCode);
If you want to get the documents where a field has a given value, you can use a query. Then once the query returns, you can get documents IDs with the .Id field on each DocumentShapshot in the returned documents.
You will also need to add await for the returned value since it is an async method returning a Task<string> not returning a string.
private async Task<string> GetDocRefAsync(string userId) {
CollectionReference usersRef = FirestoreData.GetFirestore().Collection(DBConstants.FS_COLLECTION_USERS);
Query query = usersRef.WhereEqualTo(DBConstants.FS_COLLECTION_USERS_USER_ID, userId);
// or GetSnapshotAsync depending on the version of firebase
QuerySnapshot querySnapshot = await query.Get();
// Note: if it matches multiple documents this will just return
// the ID of the first match
foreach (DocumentSnapshot item in snapshot.Documents)
{
return item.Id;
}
Log.Debug("UpdateGroupAsync", "userId: " + userId + " not found");
return null;
}
And you can use it like this to update a document (note that you were using a different collection here - probably by mistake).
string userDocId = await GetDocRefAsync(userId);
CollectionReference userCollection = database.Collection(DBConstants.FS_COLLECTION_USERS);
DocumentReference docReference = userCollection.Document(userDocId);
// or UpdateAsync depending on your version of firebase
docReference.Update(DBConstants.FS_COLLECTION_USERS_GROUPS_CODE, groupCode);
Hallo guys!
Sorry for the dump question, this is my last resort. I swear i triend countless of other Stackoverflow questions, different Frameworks, etc., but those didnt seem to help.
Ich have the following Problem:
A website displays a list of data (there is a TON of div, li, span etc. tags infront, its a big HTML.)
Im writing a tool that fetches data from a specific list inside a ton of other div tags, downloads it and outputs an excel file.
The website im trying to access, is dynamic. So you open the website, it loads a little bit, and then the list appears (probably some JS and stuff).
When i try to download the website via a webRequest in C#, the html I get ist almost empty with a ton on white spaces, lots of non-html stuff, some garbage data as well.
Now: Im pretty used to C#, HTMLAgillityPack, and countless other libraries, not so much in web related stuff tho. I tried CefSharp, Chromium etc. all of those stuff, but couldnt get them to work properly unfortunately.
I want to have a HTML in my program to work with that looks exactly like the HTML that you see when
you open the dev console in chrome wenn visting the website mentined above.
The HTML parser works flwalessly there.
This is how I image how the code could look like simplified.
Extreme C# pseudocode:
WebBrowserEngine web = new WebBrowserEngine()
web.LoadURLuntilFinished(url); // with all the JS executed and stuff
String html = web.getHTML();
web.close();
My Goal would be that the string html in the pseudocode looks exactly like the one in the Chrome dev tab.
Maybe there is a solution posted somewhere else but i swear i coudlnt find it, been looking for days.
Andy help is greatly appreciated.
#SpencerBench is spot on in saying
It could be that the page is using some combination of scroll state, element visibility, or element positions to trigger content loading. If that's the case, then you'll need to figure out what it is and trigger it programmatically.
To answer the question for your specific use case, we need to understand the behaviour of the page you want to scrape data from, or as I asked in the comments, how do you know the page is "finished"?
However, it's possible to give a fairly generic answer to the question which should act as a starting point for you.
This answer uses Selenium, a package which is commonly used for automating testing of web UIs, but as they say on their home page, that's not the only thing it can be used for.
Primarily it is for automating web applications for testing purposes, but is certainly not limited to just that. Boring web-based administration tasks can (and should) also be automated as well.
The web site I'm scraping
So first we need a web site. I've created one using ASP.net core MVC with .net core 3.1, although the web site's technology stack isn't important, it's the behaviour of the page you want to scrape which is important. This site has 2 pages, unimaginatively called Page1 and Page2.
Page controllers
There's nothing special in these controllers:
namespace StackOverflow68925623Website.Controllers
{
using Microsoft.AspNetCore.Mvc;
public class Page1Controller : Controller
{
public IActionResult Index()
{
return View("Page1");
}
}
}
namespace StackOverflow68925623Website.Controllers
{
using Microsoft.AspNetCore.Mvc;
public class Page2Controller : Controller
{
public IActionResult Index()
{
return View("Page2");
}
}
}
API controller
There's also an API controller (i.e. it returns data rather than a view) which the views can call asynchronously to get some data to display. This one just creates an array of the requested number of random strings.
namespace StackOverflow68925623Website.Controllers
{
using Microsoft.AspNetCore.Mvc;
using System;
using System.Collections.Generic;
using System.Text;
[Route("api/[controller]")]
[ApiController]
public class DataController : ControllerBase
{
[HttpGet("Create")]
public IActionResult Create(int numberOfElements)
{
var response = new List<string>();
for (var i = 0; i < numberOfElements; i++)
{
response.Add(RandomString(10));
}
return Ok(response);
}
private string RandomString(int length)
{
var sb = new StringBuilder();
var random = new Random();
for (var i = 0; i < length; i++)
{
var characterCode = random.Next(65, 90); // A-Z
sb.Append((char)characterCode);
}
return sb.ToString();
}
}
}
Views
Page1's view looks like this:
#{
ViewData["Title"] = "Page 1";
}
<div class="text-center">
<div id="list" />
<script src="~/lib/jquery/dist/jquery.min.js"></script>
<script>
var apiUrl = 'https://localhost:44394/api/Data/Create';
$(document).ready(function () {
$('#list').append('<li id="loading">Loading...</li>');
$.ajax({
url: apiUrl + '?numberOfElements=20000',
datatype: 'json',
success: function (data) {
$('#loading').remove();
var insert = ''
for (var item of data) {
insert += '<li>' + item + '</li>';
}
insert = '<ul id="results">' + insert + '</ul>';
$('#list').html(insert);
},
error: function (xht, status) {
alert('Error: ' + status);
}
});
});
</script>
</div>
So when the page first loads, it just contains an empty div called list, however the page loading trigger's the function passed to jQuery's $(document).ready function, which makes an asynchronous call to the API controller, requesting an array of 20,000 elements. While the call is in progress, "Loading..." is displayed on the screen, and when the call returns, this is replaced by an unordered list containing the received data. This is written in a way intended to be friendly to developers of automated UI tests, or of screen scrapers, because we can tell whether all the data has loaded by testing whether or not the page contains an element with the ID results.
Page2's view looks like this:
#{
ViewData["Title"] = "Page 2";
}
<div class="text-center">
<div id="list">
<ul id="results" />
</div>
<script src="~/lib/jquery/dist/jquery.min.js"></script>
<script>
var apiUrl = 'https://localhost:44394/api/Data/Create';
var requestCount = 0;
var maxRequests = 20;
$(document).ready(function () {
getData();
});
function getDataIfAtBottomOfPage() {
console.log("scroll - " + requestCount + " requests");
if (requestCount < maxRequests) {
console.log("scrollTop " + document.documentElement.scrollTop + " scrollHeight " + document.documentElement.scrollHeight);
if (document.documentElement.scrollTop > (document.documentElement.scrollHeight - window.innerHeight - 100)) {
getData();
}
}
}
function getData() {
window.onscroll = undefined;
requestCount++;
$('results2').append('<li id="loading">Loading...</li>');
$.ajax({
url: apiUrl + '?numberOfElements=50',
datatype: 'json',
success: function (data) {
var insert = ''
for (var item of data) {
insert += '<li>' + item + '</li>';
}
$('#loading').remove();
$('#results').append(insert);
if (requestCount < maxRequests) {
window.setTimeout(function () { window.onscroll = getDataIfAtBottomOfPage }, 1000);
} else {
$('#results').append('<li>That\'s all folks');
}
},
error: function (xht, status) {
alert('Error: ' + status);
}
});
}
</script>
</div>
This gives a nicer user experience because it requests data from the API controller in multiple smaller chunks, so the first chunk of data appears fairly quickly, and once the user has scrolled down to somewhere near the bottom of the page, the next chunk of data is requested, until 20 chunks have been requested and displayed, at which point the text "That's all folks" is added to the end of the unordered list. However this is more difficult to interact with programmatically because you need to scroll the page down to make the new data appear.
(Yes, this implementation is a bit buggy - if the user gets to the bottom of the page too quickly then requesting the next chunk of data doesn't happen until they scroll up a bit. But the question isn't about how to implement this behaviour in a web page, but about how to scrape the displayed data, so please forgive my bugs.)
The scraper
I've implemented the scraper as a xUnit unit test project, just because I'm not doing anything with the data I've scraped from the web site other than Asserting that it is of the correct length, and therefore proving that I haven't prematurely assumed that the web page I'm scraping from is "finished". You can put most of this code (other than the Asserts) into any type of project.
Having created your scraper project, you need to add the Selenium.WebDriver and Selenium.WebDriver.ChromeDriver nuget packages.
Page Object Model
I'm using the Page Object Model pattern to provide a layer of abstraction between functional interaction with the page and the implementation detail of how to code that interaction. Each of the pages in the web site has a corresponding page model class for interacting with that page.
First, a base class with some code which is common to more than one page model class.
namespace StackOverflow68925623Scraper
{
using System;
using OpenQA.Selenium;
using OpenQA.Selenium.Support.UI;
public class PageModel
{
protected PageModel(IWebDriver driver)
{
this.Driver = driver;
}
protected IWebDriver Driver { get; }
public void ScrollToTop()
{
var js = (IJavaScriptExecutor)this.Driver;
js.ExecuteScript("window.scrollTo(0, 0)");
}
public void ScrollToBottom()
{
var js = (IJavaScriptExecutor)this.Driver;
js.ExecuteScript("window.scrollTo(0, document.body.scrollHeight)");
}
protected IWebElement GetById(string id)
{
try
{
return this.Driver.FindElement(By.Id(id));
}
catch (NoSuchElementException)
{
return null;
}
}
protected IWebElement AwaitGetById(string id)
{
var wait = new WebDriverWait(Driver, TimeSpan.FromSeconds(10));
return wait.Until(e => e.FindElement(By.Id(id)));
}
}
}
This base class gives us 4 convenience methods:
Scroll to the top of the page
Scroll to the bottom of the page
Get the element with the supplied ID, or return null if it doesn't exist
Get the element with the supplied ID, or wait for up to 10 seconds for it to appear if it doesn't exist yet
And each page in the web site has its own model class, derived from that base class.
namespace StackOverflow68925623Scraper
{
using OpenQA.Selenium;
public class Page1Model : PageModel
{
public Page1Model(IWebDriver driver) : base(driver)
{
}
public IWebElement AwaitResults => this.AwaitGetById("results");
public void Navigate()
{
this.Driver.Navigate().GoToUrl("https://localhost:44394/Page1");
}
}
}
namespace StackOverflow68925623Scraper
{
using OpenQA.Selenium;
public class Page2Model : PageModel
{
public Page2Model(IWebDriver driver) : base(driver)
{
}
public IWebElement Results => this.GetById("results");
public void Navigate()
{
this.Driver.Navigate().GoToUrl("https://localhost:44394/Page2");
}
}
}
And the Scraper class:
namespace StackOverflow68925623Scraper
{
using OpenQA.Selenium.Chrome;
using System;
using System.Threading;
using Xunit;
public class Scraper
{
[Fact]
public void TestPage1()
{
// Arrange
var driver = new ChromeDriver();
var page = new Page1Model(driver);
page.Navigate();
try
{
// Act
var actualResults = page.AwaitResults.Text.Split(Environment.NewLine);
// Assert
Assert.Equal(20000, actualResults.Length);
}
finally
{
// Ensure the browser window closes even if things go pear-shaped
driver.Quit();
}
}
[Fact]
public void TestPage2()
{
// Arrange
var driver = new ChromeDriver();
var page = new Page2Model(driver);
page.Navigate();
try
{
// Act
while (!page.Results.Text.Contains("That's all folks"))
{
Thread.Sleep(1000);
page.ScrollToBottom();
page.ScrollToTop();
}
var actualResults = page.Results.Text.Split(Environment.NewLine);
// Assert - we expect 1001 because of the extra "that's all folks"
Assert.Equal(1001, actualResults.Length);
}
finally
{
// Ensure the browser window closes even if things go pear-shaped
driver.Quit();
}
}
}
}
So, what's happening here?
// Arrange
var driver = new ChromeDriver();
var page = new Page1Model(driver);
page.Navigate();
ChromeDriver is in the Selenium.WebDriver.ChromeDriver package and implements the IWebDriver interface from the Selenium.WebDriver package with the code to interact with the Chrome browser. Other packages are available containing implementations for all popular browsers. Instantiating the driver object opens a browser window, and calling its Navigate method directs the browser to the page we want to test/scrape.
// Act
var actualResults = page.AwaitResults.Text.Split(Environment.NewLine);
Because on Page1, the results element doesn't exist until all the data has been displayed, and no user interaction is required in order for it to be displayed, we use the page model's AwaitResults property to just wait for that element to appear and return it once it has appeared.
AwaitResults returns an IWebElement instance representing the element, which in turn has various methods and properties we can use to interact with the element. In this case we use its Text property which returns the element's contents as a string, without any markup. Because the data is displayed as an unordered list, each element in the list is delimited by a line break, so we can can use String's Split method to convert it to a string array.
Page2 needs a different approach - we can't use the presence of the results element to determine whether the data has all been displayed, because that element is on the page right from the start, instead we need to check for the string "That's all folks" which is written right at the end of the last chunk of data. Also the data isn't loaded all in one go, and we need to keep scrolling down in order to trigger the loading of the next chunk of data.
// Act
while (!page.Results.Text.Contains("That's all folks"))
{
Thread.Sleep(1000);
page.ScrollToBottom();
page.ScrollToTop();
}
var actualResults = page.Results.Text.Split(Environment.NewLine);
Because of the bug in the UI that I mentioned earlier, if we get to the bottom of the page too quickly, the fetch of the next chunk of data isn't triggered, and attempting to scroll down when already at the bottom of the page doesn't raise another scroll event. That's why I'm scrolling to the bottom of the page and then back to the top - that way I can guarantee that a scroll event is raised. You never know, the web site you're trying to scrape data from may itself be buggy.
Once the "That's all folks" text has appeared, we can go ahead and get the results element's Text property and convert it to a string array as before.
// Assert - we expect 1001 because of the extra "that's all folks"
Assert.Equal(1001, actualResults.Length);
This is the bit that won't be in your code. Because I'm scraping a web site which is under my control, I know exactly how much data it should be displaying so I can check that I've got all the data, and therefore that my scraping code is working correctly.
Further reading
Absolute beginner's introduction to Selenium: https://www.guru99.com/selenium-csharp-tutorial.html
(A curiosity in that article is the way that it starts by creating a console application project and later changes its output type to class library and manually adds the unit test packages, when the project could have been created using one of Visual Studio's unit test project templates. It gets to the right place in the end, albeit via a rather odd route.)
Selenium documentation: https://www.selenium.dev/documentation/
Happy scraping!
If you need to fully execute the web page, then a complete browser like CefSharp is your only option.
It could be that the page is using some combination of scroll state, element visibility, or element positions to trigger content loading. If that's the case, then you'll need to figure out what it is and trigger it programmatically. I know that CefSharp can simulate user actions like clicking, scrolling, etc.
I'm having issues with if submit form is available then submit data and check for response, it seems to check for submit form, submit the data but then doesn't process the response given, example of code:
if (driver.FindElements(By.Name("search")).Count > 0 && driver.FindElement(By.Name("search")).Displayed)
{
driver.FindElement(By.Name("search")).SendKeys(query + Keys.Enter);
if (driver.FindElements(By.XPath("//*[#id='not found']/h2")).Count > 0 && driver.FindElement(By.XPath("//*[#id='not found']/h2")).Displayed)
{
Console.WriteLine("search not found");
driver.Manage().Cookies.DeleteAllCookies();
driver.Navigate().GoToUrl("https://example.com");
}
}
what this should doing is:
if
driver.findelement(by.name("search")
is true, then
driver.findelement(by.name("search").sendkeys(query)
then, check for response provided and handle using given commands within the if statement.
I would rewrite this a little to make it a little more readable and not hit the page so many times. Every time you do driver.findElement(), Selenium scrapes the page. Scrape it once, do all your analysis using that first scrape, and then proceed.
IReadOnlyCollection<IWebElement> search = GetVisibleElements(By.Name("search"));
if (search.Any())
{
search.ElementAt(0).SendKeys(query + Keys.Enter);
if (GetVisibleElements(By.XPath("//*[#id='not found']/h2")).Any())
{
// search not found
Console.WriteLine("search not found");
Driver.Manage().Cookies.DeleteAllCookies();
Driver.Navigate().GoToUrl("https://example.com");
}
else
{
// search found
// do stuff here
}
}
Since you are checking more than once if an element exists and is visible, I would wrap that code in a function to make it more usable and make your code easier to read.
public IReadOnlyCollection<IWebElement> GetVisibleElements(By locator)
{
return Driver.FindElements(locator).Where(e => e.Displayed).ToList();
}
This function locates the elements based on the locator provided, filters it down to only those elements that are displayed, and then returns the list. You can then see if there are any elements in the returned list in your script.
I am trying to get all my status messages using the following code:
public dynamic downloadStatuses(FacebookOAuthResult facebookOAuthResult, string userInput)
{
dynamic result = null;
if (facebookOAuthResult != null)
{
if (facebookOAuthResult.IsSuccess)
{
this.accessToken = facebookOAuthResult.AccessToken;
var fb = new FacebookClient(facebookOAuthResult.AccessToken);
result = fb.Get(userInput + "/statuses?format=json&limit=1500");
return result;
}
else
{
MessageBox.Show(facebookOAuthResult.ErrorDescription);
return result;
}
}
return result;
}
userInput would be my Facebook ID. Some statuses are returned but definitely does not total up to the 1500 that I have indicated. Was wondering if anyone knew how to access your first ever facebook status message or retrieve all the status message by slightly modifying the request url in the code. Is it a must to use fql?
When you query /statuses you don't get the Photo/Album/video related statuses/entries from your stream (including their comments etc). This also includes event creation and questions.
You will have to query the API with separate calls (i.e. /me/photos) to get everything. If you want to have almost the full stream of some person or page or group. Consider using FQL, querying the stream table.
EDIT : Just saw this question is probably outdated, my bad