upload blobs with go - azure

I'm building an API written in go and gin, which uploads blobs to Azure Storage. Here is the code:

package main
import (
"context"
"fmt"
"log"
"net/http"
"net/url"
"github.com/Azure/azure-storage-blob-go/azblob"
"github.com/gin-gonic/gin"
)
func main() {
router := gin.Default()
router.POST("/upload", func(c *gin.Context) {
accountName := "blablabla"
accountKey := "mykey"
containerName := "testblabla"
blobName := c.PostForm("blobName")
credential, err := azblob.NewSharedKeyCredential(accountName, accountKey)
if err != nil {
log.Fatal("Erro ao realizar nova conexão com azure", err)
return
} else {
fmt.Println("Sucesso ao se conectar com o azure")
}
u, err := url.Parse(fmt.Sprintf("https://%s.blob.core.windows.net/%s/%s", accountName, containerName, blobName))
if err != nil {
c.JSON(http.StatusInternalServerError, gin.H{
"Erro ao ler URL do container": err,
})
log.Fatal("Erro ao ler URL do container", err)
return
} else {
fmt.Println("Sucesso ao ler URL do container, eu passei por aqui")
c.JSON(200, gin.H{
"Sucesso ao ler URL do container": "Eu passei por aqui",
})
}
blobURL := azblob.NewBlockBlobURL(*u, azblob.NewPipeline(credential, azblob.PipelineOptions{}))
c.JSON(200, gin.H{
"Sucesso ao ler URL do container": "Próximo passo",
})
log.Println("Sucesso ao ler URL do container")
form, err := c.MultipartForm()
if err != nil {
c.JSON(http.StatusInternalServerError, gin.H{
"Erro ao ler arquivo": err.Error(),
})
log.Println("Erro ao ler arquivo", err)
return
}
files := form.File["upload"]
if len(files) == 0 {
c.JSON(http.StatusBadRequest, gin.H{
"Erro ao enviar arquivo para container": "Nenhum arquivo enviado",
})
log.Println("Nenhum arquivo enviado", err)
return
}
file := files[0]
fmt.Println("eu passei por files", file)
log.Println(file.Filename)
src, err := file.Open()
if err != nil {
c.JSON(500, gin.H{
"Erro ao abrir arquivo": err,
})
log.Fatal("Erro ao abrir arquivo", err)
return
} else {
fmt.Println("Sucesso ao abrir arquivo")
c.JSON(200, gin.H{
"Sucesso ao abrir arquivo": "Proximo passo",
})
}
options := azblob.UploadStreamToBlockBlobOptions{
MaxBuffers: 3,
}
_, err = azblob.UploadStreamToBlockBlob(context.Background(), src, blobURL, options)
if err != nil {
fmt.Println("deu erro, mas passei por aqui")
c.JSON(http.StatusInternalServerError, "Deu erro, mas passei aqui")
c.JSON(http.StatusInternalServerError, gin.H{
"Erro ao enviar arquivo para container": err.Error(),
})
log.Println("Erro ao enviar arquivo para container", err)
return
} else {
c.JSON(http.StatusOK, gin.H{
"message": "Arquivo enviado com sucesso!",
})
fmt.Println("Sucesso ao enviar arquivo")
}
})
router.Run(":8080")
}

Here are the steps to test this API with Postman:

1. Select POST as the method
2. Enter the URL of the API
3. Select form-data under the body tab
4. In the key column I put the name of the blob, and select the type file, then I select my file
5. Send the request

I got this error:

Erro ao enviar arquivo para container write error: -> github.com/Azure/azure-storage-blob-go/azblob.newStorageError, C:/Users/rodri/go/pkg/mod/github.com/!azure/azure-storage-blob-go@v0.15.0/azblob/zc_storage_error.go:42
===== RESPONSE ERROR (ServiceCode=InvalidUri) =====
Description=The requested URI does not represent any resource on the server.
RequestId:a31b34a1-401e-000c-3aa8-6fb698000000
Time:2023-04-15T14:43:41.9699330Z, Details:
Code: InvalidUri
UriPath: https://blablabla.blob.core.windows.net/teste/?blockid=mLa1s8Y9Tu6Tqw0umZ2kiwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA==&comp=block&timeout=61        
PUT https://blablabla.blob.core.windows.net/teste/?blockid=mLa1s8Y9Tu6Tqw0umZ2kiwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA%3D%3D&comp=block&timeout=61
Authorization: REDACTED
Content-Length: [5]
User-Agent: [Azure-Storage/0.15 (go1.20; Windows_NT)]
X-Ms-Client-Request-Id: [5e531a97-f854-476c-49f7-407a29468e89]
X-Ms-Date: [Sat, 15 Apr 2023 14:43:41 GMT]
X-Ms-Version: [2020-10-02]
--------------------------------------------------------------------------------
RESPONSE Status: 400 The requested URI does not represent any resource on the server.      
Content-Length: [438]
Content-Type: [application/xml]
Date: [Sat, 15 Apr 2023 14:43:41 GMT]
Server: [Microsoft-HTTPAPI/2.0]
X-Ms-Error-Code: [InvalidUri]
X-Ms-Request-Id: [a31b34a1-401e-000c-3aa8-6fb698000000]

Why?

What's wrong?

There is not a form field named blobName in the request.

blobName := c.PostForm("blobName")

Evidence

The error message is clear about this:

Code: InvalidUri
UriPath: https://blablabla.blob.core.windows.net/teste/?blockid=mLa1s8Y9Tu6Tqw0umZ2kiwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA==&comp=block&timeout=61
^^^

Comparing to

fmt.Sprintf("https://%s.blob.core.windows.net/%s/%s", accountName, containerName, blobName)
^^^

It's obviously that blobName is empty.

Explanation

This Postman request

looks like this as a raw HTTP request:

POST /anything HTTP/1.1
Host: httpbin.org
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryeobf4rJjB8V8AYfS
----WebKitFormBoundaryeobf4rJjB8V8AYfS
Content-Disposition: form-data; name="upload"; filename="sample.pdf"
<content omitted>
----WebKitFormBoundaryeobf4rJjB8V8AYfS
Content-Disposition: form-data; name="blobName"
myBlobName
----WebKitFormBoundaryeobf4rJjB8V8AYfS

If such a request is handled by your handler,

• blobName := c.PostForm("blobName") will be myBlobName

• files := form.File["upload"]; file := files[0] gets the file header describing the uploaded file

• file.Filename will be sample.pdf