skip writing empty hosts to output file

[sshbounty]

Description

This PR fixes an issue where empty lines were being written to the output file when using the -o flag. If there is no result returned for the current domain it writes empty line to the output.

Changes Made

• Added checks in writePlainHost and writePlainHostIP to skip empty hosts
• Prevents writing empty lines to output files

➜  urlfinder git:(dev) ✗ urlfinder -d list -o lists.txt

  __  _____  __   _____         __
 / / / / _ \/ /  / __(_)__  ___/ /__ ____
/ /_/ / , _/ /__/ _// / _ \/ _  / -_) __/
\____/_/|_/____/_/ /_/_//_/\_,_/\__/_/

                projectdiscovery.io

[INF] Current urlfinder version v0.0.1 (latest)
[INF] Loading provider config from /home/hisham/.config/urlfinder/provider-config.yaml
[INF] Enumerating urls for example.hackerone.com

[INF] Found 1 urls for example.hackerone.com in 1 second 716 milliseconds
[INF] Enumerating urls for nodomain.hackerone.com

[INF] Found 1 urls for nodomain.hackerone.com in 876 milliseconds 382 microseconds
[INF] Enumerating urls for api.hackerone.com
https://api.hackerone.com/assets/images/home-active-icon-4456efcf.svg
https://api.hackerone.com/assets/images/reference-active-icon-0c7da4a9.svg
https://api.hackerone.com/main-4d664bd1abb44a687600.js
https://api.hackerone.com/main-e8d9a7ae1d6552d8246b.css
https://api.hackerone.com/assets/images/getting-started-icon-8e568c9c.svg
https://api.hackerone.com/assets/fonts/effra-medium-d33322a0.woff
https://api.hackerone.com/assets/fonts/slate-7b7da4fe.ttf?-syv14m
https://api.hackerone.com/customer-customer-reference
https://api.hackerone.com/customer-resources/
https://api.hackerone.com/getting-started-hacker-api/
https://api.hackerone.com/sitemap.xml
https://api.hackerone.com/use-cases/
http://api.hackerone.com/.well-known/dnt-policy.txt
https://api.hackerone.com/assets/fonts/roboto-mono-regular-5d9f74e5.ttf
https://api.hackerone.com/assets/fonts/slate-cfc9d06b.eot?-syv14m
https://api.hackerone.com/assets/images/logo-b8de4ab7.svg
https://api.hackerone.com/assets/images/navbar-cad8cdcb.png
https://api.hackerone.com/assets/stylesheets/screen-fb7fa378.css
https://api.hackerone.com/docs/v1
https://api.hackerone.com/getting-started/
http://api.hackerone.com/.well-known/openid-configuration
http://api.hackerone.com/robots.txt
http://api.hackerone.com/v1/reports
https://api.hackerone.com/main-c3878c632ee65dcdc7a8.js
https://api.hackerone.com/assets/fonts/slate-e55b8307.svg?-syv14m
https://api.hackerone.com/favicon.ico
https://api.hackerone.com/main-5bd806ac677ea57eea5b.js
https://api.hackerone.com/main-96b79e99b3217578218b.css
https://api.hackerone.com/v1
http://api.hackerone.com/ads.txt
https://api.hackerone.com/assets/fonts/effra-regular-7ebee9e1.woff
https://api.hackerone.com/assets/javascripts/google_analytics-d319b720.js
https://api.hackerone.com/main-4d664bd1abb44a687600.css
https://api.hackerone.com/main-bf0e790bffe7dc2e208b.css
https://api.hackerone.com/reference/
http://api.hackerone.com/.well-known/assetlinks.json
http://api.hackerone.com/.well-known/security.txt
https://api.hackerone.com/assets/fonts/slate-cfc9d06b.eot
https://api.hackerone.com/assets/images/home-icon-e212aeb8.svg
https://api.hackerone.com/assets/images/rss-feed-icon-565f423d.svg
https://api.hackerone.com/assets/stylesheets/screen-bee96dd6.css

https://api.hackerone.com/assets/stylesheets/screen-0540c09c.css
https://api.hackerone.com/assets/stylesheets/screen-176a6d12.css
https://api.hackerone.com/main-71b11a887fec26ab0ef8.css
https://api.hackerone.com/assets/stylesheets/print-c3fe4d09.css
https://api.hackerone.com/assets/fonts/slate-33847ce5.woff?-syv14m
https://api.hackerone.com/assets/images/reference-icon-740a9c21.svg
https://api.hackerone.com/assets/images/rss-feed-active-icon-54a5ccb1.svg
http://api.hackerone.com/.well-known/ai-plugin.json
http://api.hackerone.com/.well-known/nodeinfo
http://api.hackerone.com/.well-known/trust.txt
https://api.hackerone.com/core-resources/
https://api.hackerone.com/main-71b11a887fec26ab0ef8.js
https://api.hackerone.com/
https://api.hackerone.com/assets/images/webhooks-icon-b2932429.svg
https://api.hackerone.com/main-96b79e99b3217578218b.js
http://api.hackerone.com/v1/reports?filter
http://api.hackerone.com/.well-known/gpc.json
https://api.hackerone.com/assets/images/favicon.ico
https://api.hackerone.com/assets/images/resources-icon-eb571889.svg
https://api.hackerone.com/assets/images/webhooks-active-icon-6fb884a3.svg
https://api.hackerone.com/assets/javascripts/all-3193d32d.js
https://api.hackerone.com/customer-reference/
https://api.hackerone.com/main-5bd806ac677ea57eea5b.css
http://api.hackerone.com/app-ads.txt
https://api.hackerone.com/assets/images/resources-active-icon-8f1980c4.svg
https://api.hackerone.com/assets/images/use-cases-active-icon-f422508f.svg
https://api.hackerone.com/assets/javascripts/all-55afcf84.js
https://api.hackerone.com/webhooks
https://api.hackerone.com/assets/images/getting-started-active-icon-8c622cd1.svg
https://api.hackerone.com/main-e8d9a7ae1d6552d8246b.js
https://api.hackerone.com/assets/stylesheets/print-3db2b047.css
https://api.hackerone.com/assets/stylesheets/screen-4e8bb72e.css
https://api.hackerone.com/hacker-resources/
https://api.hackerone.com/main-c3878c632ee65dcdc7a8.css
https://api.hackerone.com/assets/images/use-cases-icon-27cdd84f.svg
https://api.hackerone.com/changelog.rss
https://api.hackerone.com/assets/javascripts/all-cc9d7a50.js
https://api.hackerone.com/assets/stylesheets/print-2da1ecc5.css
https://api.hackerone.com/assets/stylesheets/screen-9606ca24.css
https://api.hackerone.com/hacker-reference/
https://api.hackerone.com/assets/fonts/slate-33847ce5.woff2?-syv14m
[INF] Found 83 urls for api.hackerone.com in 1 second 725 milliseconds
[INF] Enumerating urls for noexist.hackerone.com

[INF] Found 1 urls for noexist.hackerone.com in 1 second 302 milliseconds

➜  urlfinder git:(dev) ✗ cat list
example.hackerone.com
nodomain.hackerone.com
api.hackerone.com
noexist.hackerone.com

[dogancanbakir]

@sshbounty Thanks for the PR -left a comment for you!