feat(ui): path prefix support via HTTP header (#4497)

Makes the web app honour the `X-Forwarded-Prefix` HTTP request header that may be sent by a reverse-proxy in order to inform the app that its public routes contain a path prefix.
For instance this allows to serve the webapp via a reverse-proxy/ingress controller under a path prefix/sub path such as e.g. `/localai/` while still being able to use the regular LocalAI routes/paths without prefix when directly connecting to the LocalAI server.

Changes:
* Add new `StripPathPrefix` middleware to strip the path prefix (provided with the `X-Forwarded-Prefix` HTTP request header) from the request path prior to matching the HTTP route.
* Add a `BaseURL` utility function to build the base URL, honouring the `X-Forwarded-Prefix` HTTP request header.
* Generate the derived base URL into the HTML (`head.html` template) as `<base/>` tag.
* Make all webapp-internal URLs (within HTML+JS) relative in order to make the browser resolve them against the `<base/>` URL specified within each HTML page's header.
* Make font URLs within the CSS files relative to the CSS file.
* Generate redirect location URLs using the new `BaseURL` function.
* Use the new `BaseURL` function to generate absolute URLs within gallery JSON responses.

Closes #3095

TL;DR:
The header-based approach allows to move the path prefix configuration concern completely to the reverse-proxy/ingress as opposed to having to align the path prefix configuration between LocalAI, the reverse-proxy and potentially other internal LocalAI clients.
The gofiber swagger handler already supports path prefixes this way, see e2d9e9916d/swagger.go (L79)

Signed-off-by: Max Goltzsche <max.goltzsche@gmail.com>
This commit is contained in:
Max Goltzsche 2025-01-07 17:18:21 +01:00 committed by GitHub
parent bf37eebecb
commit 8cc2d01caa
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37 changed files with 416 additions and 105 deletions

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@ -8,6 +8,7 @@ import (
"github.com/gofiber/fiber/v2"
"github.com/gofiber/fiber/v2/middleware/keyauth"
"github.com/mudler/LocalAI/core/config"
"github.com/mudler/LocalAI/core/http/utils"
)
// This file contains the configuration generators and handler functions that are used along with the fiber/keyauth middleware
@ -39,7 +40,9 @@ func getApiKeyErrorHandler(applicationConfig *config.ApplicationConfig) fiber.Er
if applicationConfig.OpaqueErrors {
return ctx.SendStatus(401)
}
return ctx.Status(401).Render("views/login", nil)
return ctx.Status(401).Render("views/login", fiber.Map{
"BaseURL": utils.BaseURL(ctx),
})
}
if applicationConfig.OpaqueErrors {
return ctx.SendStatus(500)