In this article, we are going to see how we can create a custom ModelValidatorProvider that validates models based upon the rules specified in the xml files and works side-by-side with the other built-in validator providers.
- C# 8 Adds Ranges and Recursive Patterns
- Ranges easily define a sequence of data, replacing the Enumberable.Range()
- Recursive Patterns brings an F#-like construct to C#
- Recursive Patterns is an awesome feature, it giving you the flexibility to testing the data against a sequence of conditions and performing further computations based on the condition met.
- Ranges is very useful to generate sequences of numbers in the form of a collection or a list.
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Technical blogging in the era of Stack Overflow
Have you ever found a bug in your code and wanted to pause code execution to inspect the problem? If you are a developer, there’s a strong chance you have experienced or will experience this issue many, many times. While the short and sweet answer to this problem is to use a breakpoint, the longer answer is that Visual Studio actually provides multiple kinds of breakpoints and methods that let you pause your code depending on the context! Based on the different scenarios you may experience while debugging, here are some of the various ways to pause your code and set or manage a breakpoint in Visual Studio 2017
AI-Powered Regular Expression Solver
Insert your text and drag the cursor to highlight multiple strings to find matching regular expression. You can also click on the highlighted text to remove it.
چند روزی بود که ایمیل‌های سایت رد نمی‌شدند و تمام آن‌هایی که متعلق به جی‌میل بودند، برگشت می‌خورند. در لاگ‌های سرور، اطلاعات خاصی مشاهده نشد. به همین جهت logging مخصوص SMTP Server فعال شد:
پس از یک روز، چنین سطرهایی پس از سعی‌های ارسال ایمیل به جی‌میل، قابل مشاهده بودند:
550-5.7.1+This+message+does+not+have+authentication+information+or+fails+to+pass
SPF چیست؟
SPF یا Sender Framework Policy، رکوردهای مخصوص DNS ای هستند که مشخص می‌کنند کدام میل سرورها، بر اساس نام دومین جاری، مجاز هستند ایمیل ارسال کنند. برای مثال اگر کلاینتی با IP1 سعی کند خودش را بجای دومین شما با IP0، معرفی کند و ایمیل ارسال کند، ایمیل‌های او برگشت خواهند خورد. در این حالت این کلاینت، پیام‌های خطایی شروع شده‌ی با عبارات زیر را دریافت خواهد کرد:
550-5.7.1 This message does not have authentication information or fails to pass 550-5.7.1 SPF Failed validation status=bounced (host gmail-smtp-in.l.google.com said: 550-5.7.1 This message does not have authentication information or fails to pass 550-5.7.1 authentication checks. To best protect our users from spam, the 550-5.7.1 message has been blocked. Please visit 550-5.7.1 https://support.google.com/mail/answer/81126#authentication for more 550 5.7.1 information.
چگونه باید SPF را تنظیم کرد؟
برای این منظور نیاز است به پنل تنظیمات دومین خریداری شده‌ی خود دسترسی داشته باشید و بتوانید در آنجا یک DNS Record جدید از نوع TXT را اضافه کنید؛ با این مشخصات:
Name/Host/Alias: @ Time to Live (TTL): 3600 or leave the default Value/Answer/Destination: v=spf1 ip4:xx.xx.xx.xx include:_spf.google.com ~all
چگونه بررسی کنیم که رکورد SPF دومین ما به درستی تنظیم شده‌است؟
برای این منظور می‌توان از ابزار Check MX گوگل، استفاده کرد:
https://toolbox.googleapps.com/apps/checkmx/check
Microsoft Brings AI to Visual Studio with IntelliCode
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system design tutorials
7 videos
This series of videos covers of the the most important concepts related to system design, with a focus on practical system design knowledge for interviews. These system design videos cover topics like vertical vs horizontal scaling, load balancers, database design and scaling, caching, back of the envelope math for estimating capacity requirements for a system, an introduction to distributed systems, and some system design interview style questions walking through a full design implementation
