error for adding external Javascript

[z267xu]

1. If we set external Javascript in
   Dash$new(external_scripts = "your_own_js"),
   we would have error like:

"Error in as.character(function (description, open = "", blocking = TRUE, : cannot coerce type 'closure' to vector of type 'character'"

The error comes from generate_js_dist_html function in dashR package utils file. The reason is the typo in sprintf, which should be href instead of url.

dashR/R/utils.R

Lines 513 to 520 in 6bc44b5

	generate_js_dist_html <- function(href,
	local = FALSE,
	local_path = NULL,
	prefix = NULL) {
	if (!(local)) {
	if (grepl("^(?:http(s)?:\\/\\/)?[\\w.-]+(?:\\.[\\w\\.-]+)+[\\w\\-\\._~:/?#[\\]@!\\$&'\\(\\)\\*\\+,;=.]+$", href, perl=TRUE)) {
	sprintf("<script src=\"%s\"></script>", url)
	}

2. Also if we mix resources with attributes like src, integrity, crossorigin, etc, like:

external_scripts <- list(list(
src = 'https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.core.js',
integrity = 'sha256-Qqd/EfdABZUcAxjOkMi8eGEivtdTkh3b65xCZL4qAQA=',
crossorigin = 'anonymous'))

Dash$new(external_scripts = external_scripts)

we may have error like

"warning: the condition has length > 1 and only the first element will be used from if (grepl("^(?:http(s)?:\/\/)?[\w.-]+(?:\.[\w\.-]+)+[\w\-\._~:/?#[\]@!\$&'\(\)\*\+,;=.]+$",
error: values must be length 1,
but FUN(X[[2]]) result is length 4 from vapply(self$config$external_stylesheets, generate_css_dist_html,"

I guess we should manipulate input href before we call function generate_js_dist_html() and generate_css_dist_html()

dashR/R/utils.R

Lines 492 to 532 in 6bc44b5

	generate_css_dist_html <- function(href,
	local = FALSE,
	local_path = NULL,
	prefix = NULL) {
	if (!(local)) {
	if (grepl("^(?:http(s)?:\\/\\/)?[\\w.-]+(?:\\.[\\w\\.-]+)+[\\w\\-\\._~:/?#[\\]@!\\$&'\\(\\)\\*\\+,;=.]+$", href, perl=TRUE)) {
	sprintf("<link href=\"%s\" rel=\"stylesheet\">", href)
	}
	else
	stop(sprintf("Invalid URL supplied in external_stylesheets. Please check the syntax used for this parameter."), call. = FALSE)
	} else {
	# strip leading slash from href if present
	href <- sub("^/", "", href)
	modified <- as.integer(file.mtime(local_path))
	sprintf("<link href=\"%s%s?m=%s\" rel=\"stylesheet\">",
	prefix,
	href,
	modified)
	}
	}
	generate_js_dist_html <- function(href,
	local = FALSE,
	local_path = NULL,
	prefix = NULL) {
	if (!(local)) {
	if (grepl("^(?:http(s)?:\\/\\/)?[\\w.-]+(?:\\.[\\w\\.-]+)+[\\w\\-\\._~:/?#[\\]@!\\$&'\\(\\)\\*\\+,;=.]+$", href, perl=TRUE)) {
	sprintf("<script src=\"%s\"></script>", url)
	}
	else
	stop(sprintf("Invalid URL supplied. Please check the syntax used for this parameter."), call. = FALSE)
	} else {
	# strip leading slash from href if present
	href <- sub("^/", "", href)
	modified <- as.integer(file.mtime(local_path))
	sprintf("<script src=\"%s%s?m=%s\"></script>",
	prefix,
	href,
	modified)
	}
	}

@rpkyle

[rpkyle]

@z267xu Thanks for this report, very helpful.

(1) I had run into the href vs. url issue previously, and I think I resolved it locally but the commits hadn't been pushed yet. I opened a PR and merged a fix for this one.

(2) These attributes were added to Dash for Python in August 2018, so I should've incorporated them in Dash for R as well! Thanks for noting this. I think it might merit an issue so I don't lose track of it, will fix.

https://github.com/plotly/dash/blob/558047fe831f2dfe1a063af317787388bf391c10/dash/dash.py#L185-L189

[rpkyle]

Item (1) above was resolved some time ago, an issue (#98) exists for (2), so closing this issue as a duplicate.