mattwparas · mattwparas · Jun 23, 2025 · Jun 17, 2025 · Jun 17, 2025 · Jun 17, 2025
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/cogs/installer/package.scm b/cogs/installer/package.scm
@@ -15,6 +15,8 @@
                   run-dylib-installation
                   find-dylib-name))
 
+(require-builtin steel/http as http.)
+
 ;; Used for detecting if directories/files have changed
 (require "crypt.scm")
 
@@ -147,11 +149,80 @@
 
   destination)
 
+(define (find pred lst)
+  (cond
+    [(null? lst) #f]
+    [(pred (car lst)) (car lst)]
+    [else (find pred (cdr lst))]))
+
 (define (install-dylib-from-spec package dylib-dependency)
 
   (displayln "Attempting to install: " dylib-dependency)
 
   (cond
+    ; If we have urls for dylibs, instead of manually installing
+    ; the dylibs with Cargo
+    ;
+    ; We will download files at the specified `url` into the correct `dylib-path`
+    [(hash-contains? dylib-dependency '#:urls)
+
+      ; Name of the dylib dependency.
+      ;
+      ; Excludes:
+      ; - File extension (e.g. `".dll"`)
+      ; - Prefix (e.g. `"lib"`)
+     (define dylib-name (hash-ref dylib-dependency '#:name))
+
+     ; e.g. `x86_64-linux`
+     (define target
+       (string-append
+         (target-arch!)
+         "-"
+         (current-os!)))
+
+     ; Example:
+     ;
+     ; (
+     ;  #:platform
+     ;  "x86_64-linux"
+     ;  #:url
+     ;  "https://example.com/example.so"
+     ; )
+     (define url-entry
+       (find (lambda (url-entry)
+             (let ([m (apply hash url-entry)])
+               (string=? (hash-ref m '#:platform) target)))
+           (hash-ref dylib-dependency '#:urls)))
+
+     (unless url-entry
+       (displayln "dylib not found for target: " target
+       (return! void)))
+
+     ; URL to the dylib, e.g. `"https://example.com/example.so"`
+     (define url (hash-ref (apply hash url-entry) '#:url))
+
+     ; Must be `https` connection, otherwise the file could be spoofed
+     ; to serve a malicious dylib
+     (unless
+       (starts-with? url "https")
+       (displayln "url " url " must be `https://` for security purposes")
+       (return! void))
+
+     ; Where the dylib will be downloaded
+     ;
+     ; e.g. `"~/.steel/native/libexample.so"`
+     (define dylib-path
+       (string-append
+         *DYLIB-DIR*
+         (path-separator)
+         (platform-dll-prefix!)
+         dylib-name
+         "."
+         (platform-dll-extension!)))
+
+     (http.download-file! url dylib-path)
+    ]
+
     [(hash-contains? dylib-dependency '#:git-url)
      (download-and-install-library (hash-ref dylib-dependency '#:name)
                                    (hash-ref dylib-dependency '#:git-url)

diff --git a/crates/forge/Cargo.toml b/crates/forge/Cargo.toml
@@ -6,10 +6,10 @@ version.workspace = true
 [dependencies]
 # TODO: Don't use the workspace, instead explicitly
 # depend on the version with the git dependency
-steel-core = { path = "../steel-core", version = "0.7.0", features = ["dylibs", "stacker", "sync", "git"] }
+steel-core = { path = "../steel-core", version = "0.7.0", features = ["dylibs", "stacker", "sync", "git", "ureq"] }
 
 [build-dependencies]
-steel-core = { path = "../steel-core", version = "0.7.0", features = ["dylibs", "stacker", "sync", "git"] }
+steel-core = { path = "../steel-core", version = "0.7.0", features = ["dylibs", "stacker", "sync", "git", "ureq"] }
 
 [features]
 default = ["dylib-build"]

diff --git a/crates/steel-core/Cargo.toml b/crates/steel-core/Cargo.toml
@@ -86,6 +86,7 @@ httparse = "1.9.4"
 compact_str = { version = "0.8.0", features = ["serde"] }
 
 git2 = { version = "0.20.2", optional = true, features = ["vendored-openssl"] }
+ureq = { version = "3.0.12", optional = true }
 
 # For the constant map
 arc-swap = "1.7.1"
@@ -132,6 +133,7 @@ rooted-instructions = []
 recycle = []
 # git = ["dep:gix", "anyhow"]
 git = ["dep:git2", "anyhow"]
+ureq = ["dep:ureq"]
 disable-arity-checking = ["steel-derive/disable-arity-checking"]
 experimental-drop-handler = []
 unsandboxed-kernel = []

diff --git a/crates/steel-core/src/primitives/http.rs b/crates/steel-core/src/primitives/http.rs
@@ -1,8 +1,9 @@
 use crate::{
     gc::{Gc, ShareableMut},
+    rerrs::ErrorKind,
     rvals::{AsRefSteelVal, Custom, IntoSteelVal, SteelByteVector, SteelHashMap, SteelString},
     steel_vm::builtin::BuiltInModule,
-    SteelVal,
+    SteelErr, SteelVal,
 };
 
 use crate::rvals::Result;
@@ -62,6 +63,39 @@
         .map(SteelVal::StringV)
 }
 
+/// Download file from a URL
+#[steel_derive::function(name = "download-file!")]
+fn download_file(url: &SteelString, file: &SteelString) -> Result<SteelVal> {
+    #[cfg(not(feature = "ureq"))]
+    {
+        Err(SteelErr::new(
+            ErrorKind::BadSyntax,
+            "download-file! is not implemented".to_string(),
+        ))
+    }
+
+    #[cfg(feature = "ureq")]
+    {
+        use std::{fs, path::PathBuf};
+
+        let url = url.as_str();
+        let file = PathBuf::from(file.as_str());
+        let contents = ureq::get(url)
+            .call()
+            .map_err(|err| {
+                SteelErr::new(ErrorKind::Io, format!("failed to call http method: {err}"))
+            })?
+            .body_mut()
+            .read_to_vec()
+            .map_err(|err| SteelErr::new(ErrorKind::Io, format!("http request failed: {err}")))?;
+
+        fs::write(file, contents)
+            .map_err(|err| SteelErr::new(ErrorKind::Io, format!("failed to write: {err}")))?;
+
+        Ok(().into())
+    }
+}
+
 #[steel_derive::function(name = "http-request-body-offset")]
 pub fn body_offset(value: &SteelVal) -> Result<SteelVal> {
     SteelRequest::as_ref(value)
@@ -189,7 +223,8 @@
         .register_native_fn_definition(BODY_OFFSET_DEFINITION)
         .register_native_fn_definition(HEADERS_DEFINITION)
         .register_native_fn_definition(RESP_HEADERS_DEFINITION)
-        .register_native_fn_definition(PARSE_HTTP_RESPONSE_DEFINITION);
+        .register_native_fn_definition(PARSE_HTTP_RESPONSE_DEFINITION)
+        .register_native_fn_definition(DOWNLOAD_FILE_DEFINITION);
 
     // module
     //     .register_native_fn_definition(TCP_CONNECT_DEFINITION)

diff --git a/crates/steel-core/src/steel_vm/primitives.rs b/crates/steel-core/src/steel_vm/primitives.rs
@@ -1916,6 +1916,12 @@ fn meta_module() -> BuiltInModule {
         )
         .register_value("get-contract-struct", SteelVal::FuncV(get_contract))
         .register_fn("current-os!", || std::env::consts::OS)
+        .register_fn("target-arch!", || std::env::consts::ARCH)
+        .register_fn("platform-dll-prefix!", || std::env::consts::DLL_PREFIX)
+        .register_fn("path-separator", || std::path::MAIN_SEPARATOR_STR)
+        .register_fn("platform-dll-extension!", || {
+            std::env::consts::DLL_EXTENSION
+        })
         .register_fn(
             "#%build-dylib",
             |_args: Vec<String>, _env_vars: Vec<(String, String)>| {