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feat: Create HTTPTransport (#53)
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@gjenkins8
gjenkins8 authored Feb 5, 2025
1 parent ff1c4f6 commit eea8e06
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Showing 9 changed files with 417 additions and 207 deletions.
94 changes: 16 additions & 78 deletions env.go
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Original file line number Diff line number Diff line change
@@ -1,73 +1,55 @@
package pdk

type extismPointer uint64
import (
"github.com/extism/go-pdk/internal/memory"
)

// extismInputLength returns the number of bytes provided by the host via its input methods.
//
//go:wasmimport extism:host/env input_length
func extismInputLength() uint64

// extismLength returns the number of bytes associated with the block of host memory
// located at `offset`.
//
//go:wasmimport extism:host/env length
func extismLength(offset extismPointer) uint64

//go:wasmimport extism:host/env length_unsafe
func extismLengthUnsafe(extismPointer) uint64

// extismAlloc allocates `length` bytes of data with host memory for use by the plugin
// and returns its offset within the host memory block.
//
//go:wasmimport extism:host/env alloc
func extismAlloc(length uint64) extismPointer

// extismFree releases the bytes previously allocated with `extism_alloc` at the given `offset`.
//
//go:wasmimport extism:host/env free
func extismFree(offset extismPointer)

// extismInputLoadU8 returns the byte at location `offset` of the "input" data from the host.
//
//go:wasmimport extism:host/env input_load_u8
func extismInputLoadU8_(offset extismPointer) uint32
func extismInputLoadU8(offset extismPointer) uint8 {
func extismInputLoadU8_(offset memory.ExtismPointer) uint32
func extismInputLoadU8(offset memory.ExtismPointer) uint8 {
return uint8(extismInputLoadU8_(offset))
}

// extismInputLoadU64 returns the 64-bit unsigned integer of the "input" data from the host.
// Note that `offset` must lie on an 8-byte boundary.
//
//go:wasmimport extism:host/env input_load_u64
func extismInputLoadU64(offset extismPointer) uint64
func extismInputLoadU64(offset memory.ExtismPointer) uint64

// extismOutputSet sets the "output" data from the plugin to the host to be the memory that
// has been written at `offset` with the given `length`.
// The memory can be immediately freed because the host makes a copy for its use.
//
//go:wasmimport extism:host/env output_set
func extismOutputSet(offset extismPointer, length uint64)
func extismOutputSet(offset memory.ExtismPointer, length uint64)

// extismErrorSet sets the "error" data from the plugin to the host to be the memory that
// has been written at `offset`.
// The memory can be immediately freed because the host makes a copy for its use.
//
//go:wasmimport extism:host/env error_set
func extismErrorSet(offset extismPointer)
func extismErrorSet(offset memory.ExtismPointer)

// extismConfigGet returns the host memory block offset for the "config" data associated with
// the key which is represented by the UTF-8 string which as been previously written at `offset`.
// The memory for the key can be immediately freed because the host has its own copy.
//
//go:wasmimport extism:host/env config_get
func extismConfigGet(offset extismPointer) extismPointer
func extismConfigGet(offset memory.ExtismPointer) memory.ExtismPointer

// extismVarGet returns the host memory block offset for the "var" data associated with
// the key which is represented by the UTF-8 string which as been previously written at `offset`.
// The memory for the key can be immediately freed because the host has its own copy.
//
//go:wasmimport extism:host/env var_get
func extismVarGet(offset extismPointer) extismPointer
func extismVarGet(offset memory.ExtismPointer) memory.ExtismPointer

// extismVarSet sets the host "var" memory keyed by the UTF-8 string located at `offset`
// to be the value which has been previously written at `valueOffset`.
Expand All @@ -79,76 +61,32 @@ func extismVarGet(offset extismPointer) extismPointer
// The memory for the value, however, should not be freed, as that erases the value from the host.
//
//go:wasmimport extism:host/env var_set
func extismVarSet(offset, valueOffset extismPointer)

// extismStoreU8 stores the byte `v` at location `offset` in the host memory block.
//
//go:wasmimport extism:host/env store_u8
func extismStoreU8_(extismPointer, uint32)
func extismStoreU8(offset extismPointer, v uint8) {
extismStoreU8_(offset, uint32(v))
}

// extismLoadU8 returns the byte located at `offset` in the host memory block.
//
//go:wasmimport extism:host/env load_u8
func extismLoadU8_(offset extismPointer) uint32
func extismLoadU8(offset extismPointer) uint8 {
return uint8(extismLoadU8_(offset))
}

// extismStoreU64 stores the 64-bit unsigned integer value `v` at location `offset` in the host memory block.
// Note that `offset` must lie on an 8-byte boundary.
//
//go:wasmimport extism:host/env store_u64
func extismStoreU64(offset extismPointer, v uint64)

// extismLoadU64 returns the 64-bit unsigned integer at location `offset` in the host memory block.
// Note that `offset` must lie on an 8-byte boundary.
//
//go:wasmimport extism:host/env load_u64
func extismLoadU64(offset extismPointer) uint64

// extismHTTPRequest sends the HTTP `request` to the Extism host with the provided `body` (0 means no body)
// and returns back the memory offset to the response body.
//
//go:wasmimport extism:host/env http_request
func extismHTTPRequest(request, body extismPointer) extismPointer

// extismHTTPStatusCode returns the status code for the last-sent `extism_http_request` call.
//
//go:wasmimport extism:host/env http_status_code
func extismHTTPStatusCode() int32

// extismHTTPHeaders returns the response headers for the last-sent `extism_http_request` call.
//
//go:wasmimport extism:host/env http_headers
func extismHTTPHeaders() extismPointer
func extismVarSet(offset, valueOffset memory.ExtismPointer)

// extismLogInfo logs an "info" string to the host from the previously-written UTF-8 string written to `offset`.
//
//go:wasmimport extism:host/env log_info
func extismLogInfo(offset extismPointer)
func extismLogInfo(offset memory.ExtismPointer)

// extismLogDebug logs a "debug" string to the host from the previously-written UTF-8 string written to `offset`.
//
//go:wasmimport extism:host/env log_debug
func extismLogDebug(offset extismPointer)
func extismLogDebug(offset memory.ExtismPointer)

// extismLogWarn logs a "warning" string to the host from the previously-written UTF-8 string written to `offset`.
//
//go:wasmimport extism:host/env log_warn
func extismLogWarn(offset extismPointer)
func extismLogWarn(offset memory.ExtismPointer)

// extismLogError logs an "error" string to the host from the previously-written UTF-8 string written to `offset`.
//
//go:wasmimport extism:host/env log_error
func extismLogError(offset extismPointer)
func extismLogError(offset memory.ExtismPointer)

// extismLogTrace logs an "error" string to the host from the previously-written UTF-8 string written to `offset`.
//
//go:wasmimport extism:host/env log_error
func extismLogTrace(offset extismPointer)
func extismLogTrace(offset memory.ExtismPointer)

// extismGetLogLevel returns the configured log level
//
Expand Down
53 changes: 53 additions & 0 deletions example/httptransport/std_main.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,53 @@
//go:build std
// +build std

// Build the example, then invoke with:
// GOOS=wasip1 GOARCH=wasm go build std_main.go
// extism call --wasi --allow-host "jsonplaceholder.typicode.com" std_main _start

package main

import (
"fmt"
"io"
"net/http"
"os"

pdk "github.com/extism/go-pdk"
pdkhttp "github.com/extism/go-pdk/http"
)

// Currently, the standard Go compiler cannot export custom functions and is limited to exporting
// `_start` via WASI. So, `main` functions should contain the plugin behavior, that the host will
// invoke by explicitly calling `_start`.
func main() {
body, err := httpGet()
if err != nil {
pdk.SetError(err)
os.Exit(1)
}

pdk.OutputString(string(body))
}

func httpGet() ([]byte, error) {
// Set the default transport to use Extism PDK HTTPTransport
//
// Alternatively, if using http.Client, specify the transport:
// client := http.Client{
// Transport: &pdkhttp.HTTPTransport{},
// }
http.DefaultTransport = &pdkhttp.HTTPTransport{}

resp, err := http.Get("https://jsonplaceholder.typicode.com/todos/1")
if err != nil {
return nil, fmt.Errorf("failed to make request: %q", err)
}

body, err := io.ReadAll(resp.Body)
if err != nil {
return nil, fmt.Errorf("failed to read request body: %q", err)
}

return body, nil
}
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