web3 preflight options request blocked by Cloudflare

[imaibou]

When trying to use the API in browser via web3.js, no call is being processed by myetherwallet.
After investigation, it turn out that the OPTIONS request made by the browser to check CORS support is not getting passed to the MyEtherWallet API endpoint, and is instead blocked by the Cloudflare server. Following is the OPTIONS request and the corresponding CloudFlare response:

Request:

OPTIONS /eth HTTP/1.1
Host: api.myetherapi.com
Connection: close
Access-Control-Request-Method: POST
Origin: null
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2837.0 Safari/537.36
Access-Control-Request-Headers: content-type
Accept: /
Accept-Encoding: gzip, deflate
Accept-Language: fr-FR,fr;q=0.8,en-US;q=0.6,en;q=0.4

Response:

HTTP/1.1 403 Forbidden
Server: CloudFront
Date: Tue, 05 Dec 2017 10:03:40 GMT
Content-Type: text/html
Content-Length: 555
Connection: close
X-Cache: Error from cloudfront
Via: 1.1 d7d3ef7b74c87e295676d270227068b9.cloudfront.net (CloudFront)
X-Amz-Cf-Id: DDvrcDeSkZnlXMvMnrbqXQmdh51Z5oKIsTFm0sWR9Ri8DlZ1YoeG3g==

<TITLE>ERROR: The request could not be satisfied</TITLE> <\h1>ERROR<\/h1> <\h2>The request could not be satisfied.<\/h2>

---

Request blocked.

---

Generated by cloudfront (CloudFront)
Request ID: DDvrcDeSkZnlXMvMnrbqXQmdh51Z5oKIsTFm0sWR9Ri8DlZ1YoeG3g==

[freeatnet]

It appears that myetherwalletapi config blocks certain regions / IP ranges from accessing it.

[tayvano]

If you hit over 200 requests / minute, you'll be blocked for ~1hr, regardless of region.

[freeatnet]

@tayvano Fairly sure I did not issue over 200 rpm at any point. Can you confirm? https://gist.github.com/freeatnet/a1f8c085617a2d30862e5c97cefc80b2

[freeatnet]

@tayvano And again today. Please check into it.

[Fi1osof]

Was blocked just after 5 minutes...

ERROR
The request could not be satisfied.
Request blocked.
Generated by cloudfront (CloudFront)
Request ID: z58hYuLjQNPnO-j1pp6sR-ud8_zL8NZeVrVTVp9KKcocgZjjS154Tw==

Where i can read limits?

[Tenareth]

For what it is worth I just had this happen to me, the source for me appears to be the example index.html that comes with myetherapi, it "monitors" all transactions and seems to refresh pretty quickly. Might want to add some type of warning that the example can get you blocked from the main api within a few minutes.