Weeks ago, I have set up my own ln node (Umbrel). Now I try to use the lightning network for receiving donations. Here start my questions.
How can I set up a donation address where donors can decide how much to donate?
(I have discovered "keysend" as a possibility. Unfortunately, it is not widely used among users. Isn't it?)
How can I create an invoice for open-ended deposits?
Please take for your answers into account, I'm an UX designer without serious developer skills.
On my donation site at https://donate.ln.rene-pickhardt.de/ you can see that I use an adopted version of lnme https://github.com/bumi/lnme which is a widget that allows users to request an invoice from your node for a certain amount.
The propper why of doing this would be via BOLT 12 offers which are currently being standardized and are similar to keysend not yet supported by all wallets / implementations.
Another way of achieving your goal is by using LNURL or lightning-address which are currently widely supported but not part of the spec. Similar to my own solution based on lnme you need a webserver for LNURL or lightning-address.
Related
I want to build a a webcrawler that goes randomly around the internet and puts broken (http statuscode 4xx) image links into a database.
So far I successfully build a scraper using the node packages request and cheerio. I understand the limitations are websites that dynamically create content, so I'm thinking to switch to puppeteer. Making this as fast as possible would be nice, but is not necessary as the server should run indefinetely.
My biggest question: Where do I start to crawl?
I want the crawler to find random webpages recursively, that likely have content and might have broken links. Can someone help to find a smart approach to this problem?
List of Domains
In general, the following services provide lists of domain names:
Alexa Top 1 Million: top-1m.csv.zip (free)
CSV file containing 1 million rows with the most visited websites according to Alexas algorithms
Verisign: Top-Level Domain Zone File Information (free IIRC)
You can ask Verisign directly via the linked page to give you their list of .com and .net domains. You have to fill out a form to request the data. If I recall correctly, the list is given free of charge for research purposes (maybe also for other reasons), but it might take several weeks until you get the approval.
whoisxmlapi.com: All Registered Domains (requires payment)
The company sells all kind of lists containing information regarding domain names, registrars, IPs, etc.
premiumdrops.com: Domain Zone lists (requires payment)
Similar to the previous one, you can get lists of different domain TLDs.
Crawling Approach
In general, I would assume that the older a website, the more likely it might be that it contains broken images (but that is already a bold assumption in itself). So, you could try to crawl older websites first if you use a list that contains the date when the domain was registered. In addition, you can speed up the crawling process by using multiple instances of puppeteer.
To give you a rough idea of the crawling speed: Let's say your server can crawl 5 websites per second (which requires 10-20 parallel browser instances assuming 2-4 seconds per page), you would need roughly two days for 1 million pages (1,000,000 / 5 / 60 / 60 / 24 = 2.3).
I don't know if that's what you're looking for, but this website renders a new random website whenever you click the New Random Website button, it might be useful if you could scrape it with puppeteer.
I recently had this question myself and was able to solve it with the help of this post. To clarify what other people have said previously, you can get lists of websites from various sources. Thomas Dondorf's suggestion to use Verisign's TLD zone file information is currently outdated, as I learned when I tried contacting them. Instead, you should look at ICANN's CZDNS. This website allows you to access TLD file information (by request) for any name, not just .com and .net, allowing you to potentially crawl more websites. In terms of crawling, as you said, Puppeteer would be a great choice.
Preface: I have a broad, college knowledge, of a handful of languages (C++, VB,C#,Java, many web languages), so go with which ever you like.
I want to make an android app that compares numbers, but in order to do that I need a database. I'm a one man team, and the numbers get updated biweekly so I want to grab those numbers off of a wiki that gets updated as well.
So my question is: how can I access information from a website using one of the languages above?
What I understand the problem to be: Some entity generates a data set (i.e. numbers) every other week and you have a need to download that data set for treatment (e.g. sorting).
Ideally, the web site maintaining the wiki would provide a Service, like a RESTful interface, to easily gather the data. If that were the case, I'd go with any language that provides easy manipulation of HTTP request & response, and makes your data manipulation easy. As a previous poster said, Java would work well.
If you are stuck with the wiki page, you have a couple of options. You can parse the HTML your browser receives (Perl comes to mind as a decent language for that). Or you can use tools built for that purpose such as the aforementioned Jsoup.
Your question also mentions some implementation details such as needing a database. Evidently, there isn't enough contextual information for me to know whether that's optimal, so I won't address this aspect of the problem.
http://jsoup.org/ is a great Java tool for accessing content on html pages
Consider https://scraperwiki.com/ - it's a site where users can contribute scrapers. It's free as long as you let your scraper be public. The results of your scraper are exposed as csv and JSON.
If you don't know what a "scraper" is, google "screen scraping" - it's a long and frustrating tradition for coders, who have dealt with the same problem you have since the beginning of networked computing.
You could check out :http://web-harvest.sourceforge.net/
For Python, BeautifulSoup is one of the most tolerant HTML parsers out there. The documentation also lists similar libraries in Ruby and Java, so you'll probably find something relevant there.
I’m trying to help a friend in his election campaign.
We mainly need a tool to manage a list of possible voters. We need to be able to:
1. Easily update details about the voters, and
2. Query for voters according to various parameters, and show and print the resulting lists
To enable campaigners to work from multiple workstations, we would like the system to be distributed, probably web based.
We would also like that to be in Hebrew, if possible.
Is there any existing tool that easily enables it?
If not, can you recommend on an easy way to implement such a tool?
(I have a solid programming knowledge, but not much time to devote to that)
You can achieve this easily with iFreeTools Creator. Just create the entities and attributes for Voters and add campaigners as users providing their Google email-id.
Regarding your requirements..
* This app is web-based. It runs on Google App Engine.
* The interface is English only, but data can be in unicode. Entity name and attribute names are also "data", so they can be in unicode too.
Other related features which might be useful in this context..
* You can import voter list using CSV files.
* Campaigners can search for voters near their workstation by filtering out records based on nearness to a geo-location.
// Disclosure : I wrote code for this web-app. Hope you like it. Feedback welcome.
Some possible answers might be found in the same question I asked in the web apps forum
I would like to extend my WinForms app, which a feature that allows me to monitor which functions are used by the users.
The idea is to count how many times e.g. a button has been clicked, or a popup was opened.
I want to know which features are used more or less often by the users.
Any ideas how this can be done? (Or even if somebody solved this problem already)
tia,
Martin
The only mechanism I can think on to do what your looking for is to use a logger like log4net / Log4PostSharp to log details to a log file on the machine, this would give you details on usage for that particular client. You would have to create a custom attribute that you could decorate your methods with that would result in something being written out to the log file, otherwise your code would end up littered with code to implement the logging!
Have a look at this article too, it uses Log4PostSharp with AOP (Aspect Oriented Programming) which would make the implementation of the logging much more cleaner (uses attributes).
http://www.codeproject.com/KB/dotnet/log4postsharp-intro.aspx
You can find some if you google for the term "application analytics" instead of "feature tracking".
I have found the following products:
includeapp.com
Software Statistics Service
Dotfuscator for .NET, DashO for Java
FusionAnalytics
Flurry Analytics
OpenSpan Desktop Analytics
DeskMetrics
EQATEC Analytics
Rapidengines
I might say that I also plan to create such a product. When it will be Beta I will add it to the list.
I am designing a Point-Of-Sale system for a small shop. The shop just have one Point-Of-Sale but often they are one to three users (sellers) in the shop. Each user have their own user account in the system so they login and logout very often. How should I design the login/logout system in a good way?
For the moment the users don't use passwords, because it takes so long time to type the password each time they login.
The Platform is Windows Vista but I would like to support Windows 7 too. We use Active Directory on the Network. The system is developed in Java/Swing for the moment, but I'm thinking about to change to C#.NET/WPF.
I am thinking about an SmartCard solution, but I don't know if that fits my situation. It would be more secure (which I like) but I don't know if it will be easy to implement and smooth to use, i.e. can I have the POS-system running in the background or started very quickly when the users switch? Are SmartCard solutions very expensive? (My customers are small shops) Is it preferred to use .NET or Java in a SmartCard solution?
What other solutions do I have other than passwords/no passwords/smartcards?
How should I design the login/logout system in a good way?
Is there any good solution using SmartCards for this purpose?
I would like suggested solutions both for C#.NET/WPF and Java/Swing platforms.
I would like suggested solutions both for Active Directory solutions and solutions that only use one user profile in Windows.
How is this problem solved in similar products? I have only seen password-solutions, but they are clumsy.
An interesting solution is to use "Fast User Switching", i.e. the capability to have multiple user sessions open on the same PC. The POS software could be launched through the Startup folder of each seller account and would stay active in each seller session.
I thought that being in a domain (i.e. using Active Directory) disables Fast User Switching, but according to The old new thing, this was true on XP only. I just checked with my Win7 machine at work: it is in a domain but still has the "switch user" menu item.
The main advantage is that if your software is already multi-user aware, you don't need to change it.
I should have made the Fast User Switching check before writing what is below, because this seems to be the simplest solution. Here are other ideas, anyway.
Another solution is what you mention of having a single Windows user but several "virtual users" that your application manages. A smart card is a good way to implement a pseudo-login. In C++, the API allows detecting the removal or insertion of a card, so the application could detect this and read the card after insertion to know who's currently in front of the computer. .NET can easily call this API through P/Invoke; I don't know much of Java, except that JNI could be a solution to call the native API if there is no managed library that publishes this capability.
What should be done is researching the different types of card and how to talk to them, as your app should use a card that does not require a PIN to be accessed (or you are back to the slow login system, except if tying a 4-digit number is not considered too slow).
I've seen restaurants where waiters insert a key into the cash register in order to be identified. I googled "cash registers" but could only find a complete solution package, rather than the components like a key reader.
An almost idiotic question is: how much security do you need ? Does it make sense to have big buttons on the first screen of the app, where people click in order to tell the system who they are ? When they are done, they click on a "Finish" button and the app goes back to the "identify" screen. I've put this at the end because it is so simplistic that it has a low probability of being useful.
I'm not familiar with a broad range of smart card provider solutions, but I know Gemalto has a .Net friendly setup. Most others are geared to Java, but support is widening.
With regards to switching user sessions and your application, it depends on how "heavy" your application is. If your app requires quite a bit of start-up time / resources then you might consider creating the basic application as a service on the machine which can run in the background continuously and then you can load a light-weight UI to interact with the service with each user session (maybe launch via Startup menu).
There is a C# project on CodeProject which provides a framework for interacting with smart card services in windows - might be interesting reading.
I had a chance to work with the Open Source Computer Vision library (OpenCV)
in one of my past projects and its "Face-Recognition" is what you're after. It is written using native code, but can be easily used with Java, .NET, Android, iOS. All you need is a webcam and a button "Switch User" with the onClickListener that will take a picture and compare it with the images of your employees. Advantage? Once the picture's taken, it gets processed in less than 10ms. And as Timores mentioned earlier, once the face is recognised, you simply switch the session. Simple yet effective solution. Good luck!
maybe you want to think about using barcode scanner... probably you already have this device on POS ... my software for bars and restaurants use barcode scanner to recognize users. You have 2 options for using: first, user must log in with own barcode card, then he can use the application ... the second is better, everyone can use application, but to print the receipt user must use barcode card. After then he is responsible for that amount on this receipt.