Hey there, let's work through this SSL error you're hitting when trying to connect your R Markdown files to WordPress via knit2wp. That "no alternative certificate subject name matches target host name" error is super common when RCurl's strict SSL verification clashes with how your site's certificate is configured. Here are the most reliable fixes to try:

1. Check Your Site's SSL Certificate Domain Coverage #

First, let's confirm if the issue stems from your site's certificate itself. Run this command in your Linux Mint terminal to see exactly which domains your site's SSL certificate covers:

openssl s_client -connect vivaelsoftwarelibre.com:443 | openssl x509 -noout -text | grep -A 10 "Subject Alternative Name"

Look for lines starting with DNS: in the output. If vivaelsoftwarelibre.com isn't listed, but a variant like www.vivaelsoftwarelibre.com is, that's the root problem! RCurl verifies that the host name matches the certificate, so you need to update your WordPress URL in R to use the domain that's actually on the certificate. For example:

library(RWordPress)
# Use the domain listed in your certificate (e.g., with www prefix)
options(WordpressLogin = c(your_username = 'your_password'),
        WordpressURL = 'https://www.vivaelsoftwarelibre.com/xmlrpc.php')

This aligns the host name with the certificate, eliminating the mismatch error.

2. Temporarily Disable SSL Verification (For Testing Only!) #

If you just need to test the connection and don't want to dig into certificate details, you can tell RCurl to skip SSL verification. Important: This is insecure for long-term use—it bypasses checks that protect you from malicious sites—but it's useful for troubleshooting. Add these lines before calling knit2wp:

library(RCurl)
# Disable SSL peer and host verification
options(RCurlOptions = list(ssl.verifypeer = FALSE, ssl.verifyhost = FALSE))

Then run your knit2wp command as usual. If this works, you know the core issue is SSL verification, and you should circle back to fixing the certificate/domain match instead of keeping this disabled permanently.

3. Update RCurl and System Dependencies #

Even if you think you have the latest version, Linux Mint's default package sources might not have the very newest CRAN build of RCurl. Let's reinstall RCurl with all dependencies, and make sure your system has the required SSL libraries first:
First, install the system-level dependency in terminal:

sudo apt-get update && sudo apt-get install libcurl4-openssl-dev

Then reinstall RCurl in R:

install.packages("RCurl", dependencies = TRUE)

Newer versions of RCurl often have better support for modern SSL certificate configurations, which might resolve the mismatch issue outright.

4. Switch to httr as an Alternative (Advanced) #

If RCurl keeps giving you grief, you can try using the httr package instead—it handles SSL more smoothly in many cases. You'll need to write a custom function to send your knitted content to WordPress via XML-RPC, but here's a quick starting point:

library(httr)
library(knitr)

# Knit your R Markdown to HTML (fragment only, no full page)
knitted_content = knit2html("your_file.Rmd", fragment.only = TRUE)

# Send to WordPress via XML-RPC
response = POST(
  url = "https://vivaelsoftwarelibre.com/xmlrpc.php",
  body = list(
    method = "wp.newPost",
    params = list(
      0,  # Blog ID (0 for single-site WordPress)
      "your_username",
      "your_password",
      list(
        post_title = "Your Post Title",
        post_content = knitted_content,
        post_status = "publish"
      )
    )
  ),
  encode = "json"
)

# Check if the request succeeded
content(response)

This skips using RWordPress/RCurl entirely and leverages httr's more modern HTTP handling.

内容的提问来源于stack exchange，提问作者antecessor