SparkPost Recipient Validation is now available both for existing SparkPost customers and for new, non-sending customers. It uses powerful data-driven analysis on billions of bounce, delivery, and engagement events daily to train our algorithm, bringing you one of the most powerful data-driven email validation tools on the market, so you can send emails smarter.

Denna artikel explains how you can get the most out of the data you’ll receive back on each validated recipient – you’ll see we classify addresses to be “valid”, “risky”, “neutral”, “undeliverable”, and “typo”. We give you a “reason” code and also a “did_you_mean” for known address typos.

API-förfrågningar

In the SparkPost web app, you can drag & drop an entire list for validation. You can also use API to validate single addresses, so you can build validation right into your address entry workflow.

A while back we came up with a Python kommandoradsverktyg using this API. We talked over what we should do for annat languages – and here we are! Let’s get started.

This Mapp för Github-förvar has working Recipient Validation API call examples in around a dozen different languages. We try to cover the mest populära tillämpliga språk.

Det gemensamma sättet att arbeta med alla dessa exempel är:

• Pick up your key from environment variable SPARKPOST_API_NYCKEL

• Make an API call to /api/v1/mottagarvalidering/singel/to validate a recipient

• Få tillbaka en svarssträng som innehåller JSON-formaterade data med resultatet

• Skriv ut resultatet

SparkPost has bibliotek for some, but not all of the languages covered here. We chose to write these examples “native” instead, so we could a) cover more languages, b) show how simple the underlying code can be, and c) enable you to see clearly the similarities and differences between languages.

Bash / Curl

Detta vinner priset för kortaste kod - den använder helt enkelt kommandoradsverktyget "curl" för att göra förfrågan och skriva ut svaret direkt till terminalen. Du kan se att utdata är en sträng som innehåller JSON; vi analyserar faktiskt inte de enskilda resultatattributen.

PHP

Trusty PHP has a few different sätt to make HTTPS API calls. Here we chose to use curl_setopt and curl_exec. (https://www.php.net/manual/en/function.curl-exec.php)

If you prefer HTTP_Request2 or pecl_http, then Postman has a built-in code generator that you can use to create similar examples – just set up a working GET request and use the “Code” button.

Python

This uses the popular requests module, which is high-level and therefore easy to use. This example checks the returned status code, converts the results JSON back into a Python dictionary object, and prints the resulting object rather than just a string.

If you prefer the built-in http.client library, Postman can generate code for that too; it’s not much longer.

Node.js

There are många olika node.js HTTP(S) libraries. I started with the older request package (using a callback function) but it’s deprecated and no longer actively maintained.  I chose the newer axios package (using löften). 

Postman can also give you a Javascript native example and Unirest, in case you prefer those.

Eftersom den här koden behöver tillgång till din API-nyckel rekommenderar vi starkt att du anropar vårt API från serversidan, aldrig från klientsidan (webbläsare/mobil enhet).

Gå

Go strives toward a philosophy of “one good way” to do something; in this case, using the built-in “batteries included” libraries net/http, encoding/json and others.

Den length is due mostly till explicit error checking clauses om err != nil {} everywhere (inga undantag LOL).

Vi deklarerar också resultatobjektstrukturen med fälttaggar, så att vi kan "unmarshala" den returnerade JSON-strängen. Vi överlagrar taggarna "results" och "errors" för att möjliggöra båda typerna av retur.

Jag gillar snabbheten, typsäkerheten och tydligheten i Go, även om koden är längre än våra tidigare exempel.

C#

I’m less familiar with C# – to me, it looks quite Java-like, rather than C-like. I was able to put this together following examples shown in the request library System.Net.Http.

Postman can auto-generate example code using RestSharp, if you prefer that.

Rubin

This was my first attempt at Ruby code; I used the Nät::http library, and followed detta exempel (which turns out to be very close till code that Postman auto-generates).

I ran into one language / library oddity that’s worth explaining. Just setting up using a URI that begins “https://” is not enough, you have to specifically set http.use_ssl = true. 

Utan detta kommer din kod att försöka skicka en begäran på port 443 - men utan att använda SSL/TLS (dvs. i klartext), och SparkPost kommer med rätta att vägra att auktorisera begäran. Försök inte detta hemma, eftersom din API-nyckel finns i Authorization-headern. Denna språk-/biblioteksfunktion kändes osäker för mig.

Java

I’ve not written any serious Java before, but it was easy to piece this together by following the general approach used in the SparkPost-bibliotek for other GET calls.

Incidentally, using VS Code as my editor / debugger worked really well for all the languages here, giving me syntax highlighting, debugger stepping / variables viewing etc. InputStreamReaderand Buffertläsareconstructs are similar to (and I assume were copied by) Go.

C / C++

This was a trip down memory lane, as I wrote a lot of C code in the 1990s, some still running deep in telecoms networks somewhere. As the C:s historia predates the modern Web, it’s not surprising that library support is a manual task. We need to download (and compile) a recent version of Libcurl, linking to an OpenSSL library – see the README for actual steps.

Detta känns som mycket arbete jämfört med moderna språk, särskilt när Go (eller Lua, eller Python, eller någon av de andra) är tillräckligt snabba för uppgifter som denna.

Den other thing I had forgotten, despite bearing the scars from previous battles, is the scariness of memory allocation! To keep the example simple, I preallocated the URL string length as 1024 characters, and bounds-checked the email address length (using strlen) before we concatenate into it (using strcat).

Vi behandlar auktoriseringssträngen med en konkatenerad API-nyckel på samma sätt ... även om vi vet att en giltig API-nyckel aldrig kommer att vara för lång ... det är inget skydd! Användarinmatning som kommer från en miljövariabel kan vara vad som helst. Du måste programmera defensivt.

A more sophisticated developer might use mallocinstead of stack variable allocation, and calculate just how long the joined strings need to be. Having to think about this extra complexity gave me a Smärta i dioderna i vänster sida; it reminded me of the risks that C programmers run every day, trying to avoid buffer overruns and unexpected side-effects. Which brings us to ..

Lua

Lua is known for its easy coexistence alongside a body of C code, and here at SparkPost, we använt Lua i stor utsträckning for Policy customisations inside our Momentum on-premises MTA. You can also use it as a stand-alone scripting language, and it’s pretty nice for that, too.

With Lua 5.3 and the luarocks package manager, we use libraries luasocket and luasec. Showing its C integration heritage, we link to our local OpenSSL library. The luarocks install process calls the gcc compiler (or whatever C compiler you are using), so adding new libraries takes a while.

The Lua code is quite simple. The characters — mark comments.  The function https.begäran provides flera returvärden (a bit like Python and Go). String concatenation is done with the operatör  .. (instead of + in Python).

The response body from this call is handled with the “ltn12” module – see here. That enables efficient handling of data that could be returned in multiple “chunks”. As that article explains:

Tabellfabriken skapar en sink som lagrar alla erhållna data i en tabell. Data kan senare effektivt konkateneras till en enda sträng med biblioteksfunktionen table.concat.

I vårt exempel sammanfogar vi bara tabell t och skriver ut den; du kan använda ett filter för att utföra mer bearbetning.

Perl

While Perl is famous for its One liners, this is not one of them.  Perl was designed for very fast document search and modification, but is actually capable of so much more.  I once wrote an entire Inventory control suite in Perl.  Go figure.   A n y w a y…

This script makes use of LWP::UserAgent and HTTP::Request and optionally the JSON and Data::Dumper packages depending on how you want to see the output. As with all the other scripts on this page, you should pre-set an environment variable SPARKPOST_API_NYCKELto your generated API key that includes the Recipient Validation function. This script hard codes $recipient = ‘test@gmail.com’ but you can easily add command-line input or consume from a file.

After all the variables are populated, we load an HTTP:Request with GET parameters and send it to the LWP:UserAgent.  The resulting “message” is the result of the email validation test as an array.  You can use JSON and DUMPER to display the result or just pass the array on for additional processing.

VB.net

Visual Basic is not visual and it is not basic (IMHO), but it is #6 on the TIOBE språkindex so here we go.

There are other ways to do this, but the easiest path to success is to use the Visual Studio SDK in a Windows platform. Fire up Visual Studio, start a new project and select Visual Basic, then select console.app.  Be sure to use the VB version not the C# version – it is easy to miss that in the SDK.

At this point you can edit lines manually or copy/paste the code från här into VS and save a bunch of time. In order to make this code work, you need to add a Windows environment variable.  The easiest way to do this is to open a command prompt and use setx.exe like this: 

C:\Users\me>setx SPARKPOST_API_NYCKEL  "142<redacted<redacted>c531c3"

I Windows 10 tillämpas detta på din användarmiljö, men är inte omedelbart tillgängligt i den aktuella kommandosessionen, så att testa det med en "set" kommer inte att fungera, men det kommer att vara tillgängligt för koden. Om du bygger och kör koden som ingår i repot kommer du att se valideringsresultatet.

Rost

Rust is a language for systems and web-services programming that is focused on performance, safety and concurrency. As Wikipedia says, Rust has been the “most loved programming language” in the Stack Overflow Developer Survey since 2016.

The Rust code i vår Github repo uses the reqwest library with Tokio async, similar to this example from the Rust cookbook. (That’s not a typo, the reqwest library name is spelled like that). We’ve included a cargo package manager konfigurationsfil, so you can build and run with:

cd rust_recipient_validation cargo kör

Detta kompilerar paketet till körbar kod och kör det:

Avslutade dev [ooptimerad + debuginfo] mål på 0,10 s Kör `target/debug/rust_recipient_validation` Status: 200 OK Kropp: : (etc)

The code uses std:envto read the SPARKPOST_API_KEY environment variable. A match clause handles the case where the key is undefined. If all is well, a new reqwest::Klient is created and an async call issued, followed by an .vänta? (see here). Async, rather than the simpler blocking call, seems to be needed to set request headers. Response body text is read with a second .vänta?, as per detta exempel.

Summary

I den här artikeln har vi gått igenom kodexempel för Recipient Validation på många språk. Här är vår förfrågan till dig.

Let us know if you think we missed your favorite language. We may not have as many examples as Fibonacci-projektet, but we’d love to add some more. Also, if you think our examples can be improved, let us know!