Personal blog written from scratch using Node.js, Bootstrap, and MySQL. https://jrtechs.net
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const pandoc = require('node-pandoc');
const utils = require('../utils/utils.js');
const sql = require('../utils/sql');
const argsFull = '--from markdown-markdown_in_html_blocks+raw_html --toc --toc-depth=3 -N --mathjax -t html5 --no-highlight';
const argsPreview = '--mathjax -t html5';
module.exports=
{
/**
* Renders the entire blog post based on the sql data pulled
* from the database.
*
* @param post sql data which has title, date, and header img location
* @param blocks number of blocks to display for a preview or -1 for
* all the blocks
* @returns {Promise} async call which renders the entire blog post.
*/
generateBlogPost: function(post, blocks)
{
return new Promise(function(resolve, reject)
{
Promise.all([module.exports.generateBlogPostHeader(post),
module.exports.generateBlogPostBody(post, blocks)])
.then(function()
{
resolve(post);
}).catch(function(error)
{
reject(error);
})
});
},
/**
* Renders the header of the blog post which contains the header image, and date
* published.
*
* @param post sql data
* @returns {string}
*/
generateBlogPostHeader: function(post)
{
if(post.picture_url !== "n/a")
post.hasPicture = true;
post.published = post.published.toDateString();
return;
},
/**
* Method which renders the body of the blog post. This is responsible for getting
* the contents of the markdown/latex file and rendering it into beautiful html.
*
* @param post stuff from the SQL table
* @param blocks
* @returns {Promise}
*/
generateBlogPostBody: function(post, blocks)
{
return new Promise(function(resolve, reject)
{
sql.getCategory(post.category_id).then(function(category)
{
module.exports.generateBlogPostComponent(category[0].url, post.url, blocks).then(function(html)
{
post.categoryURL = category[0].url;
post.blogBody = html;
resolve();
});
});
})
},
/**
* Decomposition from Generate Blog Post used for the
* blog previewer.
*
* @param categoryURL
* @param postURL
* @param blocks
* @returns {Promise}
*/
generateBlogPostComponent: function(categoryURL, postURL, blocks)
{
return new Promise(function(resolve, reject)
{
const pathName = "blogContent/posts/" + categoryURL + "/"
+ postURL + ".md";
var markDown = utils.getFileContents(pathName).toString();
markDown = markDown.split("(media/").join("(" + "../blogContent/posts/"
+ categoryURL + "/media/");
module.exports.convertToHTML(markDown, blocks).then(function(result)
{
// hackey stuff to fix this open issue on pandoc https://github.com/jgm/pandoc/issues/3858
//search for pattern <pre class="LANG"><code> and replace with <code class="language-LANG">
var re = /\<pre class=".*?"><code>/;
while (result.search(re) != -1)
{
var preTag = result.match(/\<pre class=".*?"><code>/g)[0];
var finishIndex = preTag.split('"', 2).join('"').length;
lang = preTag.substring(12, finishIndex);
var newHTML = `<pre><code class="language-${lang}">`
var original = `<pre class="${lang}"><code>`;
result = result.split(original).join(newHTML);
}
result = result.split("<figcaption>").join("<figcaption style=\"visibility: hidden;\">");
//this line prevents older versions of pandoc from including invalid cdm scripts
result = result.split("<script src=\"https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS_CHTML-full\" type=\"text/javascript\"></script>").join("");
result = result.split("<script src=\"https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML\" type=\"text/javascript\"></script>").join("");
//stuff for youtube videos
var re = /\<youtube .*?>/;
//<youtube src="" />
while (result.search(re) != -1)
{
var ytid = result.substring(result.search(re) + 14, result.search(re)+ 11 + 14);
var youtubeHTML = `
<div class="wrapper">
<div class="youtube" data-embed="${ytid}">
<div class="play-button"></div>
</div>
</div>`;
var original = `<youtube src="${ytid}" />`;
result = result.split(original).join(youtubeHTML);
}
var regExp = /\<customHTML .*?>/;
while (result.search(regExp) != -1)
{
const pathName = "blogContent/posts/" + categoryURL + "/html/"
+ postURL + ".html";
var htmlContent = utils.getFileContents(pathName).toString();
result = result.split("<customHTML />").join(htmlContent);
}
if(blocks == -1)
resolve(result);
const htmlBlocks = result.split("<p>");
var html = "";
for(var i = 0; i < blocks; i++)
{
html += "<p>" + htmlBlocks[i];
}
resolve(html);
}).catch(function(error)
{
reject(error);
})
})
},
/**
* Converts markdown into html.
*
* @param markdownContents
* @param type
* @returns {Promise}
*/
convertToHTML: function(markdownContents, type)
{
if(type == -1)
{
return module.exports.pandocWrapper(markdownContents, argsFull);
}
else
{
return module.exports.pandocWrapper(markdownContents, argsFull);
}
},
pandocWrapper: function(markdownContents, pandocArgs)
{
return new Promise((resolve, reject)=>
{
// Set your callback function
callback = function (err, html)
{
if (err)
{
reject(err);
}
if(html === undefined)
{
resolve("");
}
else
{
html = html.split("<img").join("<img style=\"max-width: 100%;\" ");
// html = html.split("<code>").join("<code class='hljs cpp'>");
resolve(html);
}
};
pandoc(markdownContents, pandocArgs, callback);
});
},
/**
* Renders a bunch of blog post previews to the user
*
* @param baseURL-- url of the page
* @param posts -- sql data about the blog to render
* @param currentPage -- the current page to render
* @param numOfPosts -- number of blog to render
* @returns {Promise} renders the html of the blog
*/
renderBatchOfPosts: function(baseURL, posts, currentPage, numOfPosts, templateContext)
{
if(typeof currentPage == "undefined")
{
currentPage = 1;
}
else
{
currentPage = Number(currentPage);
}
return new Promise(function(resolve, reject)
{
const promises = [];
for(var i = (currentPage-1) * numOfPosts; i < (currentPage-1) * numOfPosts + numOfPosts; i++)
{
if(i < posts.length)
{
promises.push(new Promise(function(res, rej)
{
module.exports.generateBlogPost(posts[i], posts.length === 1 ? -1: 3).then(function(tempContext)
{
if(posts.length != 1)
{
templateContext.preview = true
}
res(tempContext);
}).catch(function(error)
{
rej();
})
}));
}
}
Promise.all(promises).then(function(posts)
{
templateContext.posts = posts;
if(posts.length == 1)
templateContext.title = posts[0].name;
else if(currentPage != 1 && baseURL === "/")
templateContext.title = "page " + currentPage;
resolve();
}).catch(function(error)
{
reject(error);
});
});
}
};